Effect of Friction Stir Welding on Dynamic
ABSTRACT. A split Hopkinson pressure bar or Kolsky bar system was used to de-termine the dynamic compressive flow b e h a vior of two materials. Dynamic,compressive stress-strain curves were ob-tained of AA2024-T3 and AA7075-T7351 aluminum alloys and their welds as produced by the friction stir welding process. To show the strain rate effect,quasistatic tests of these materials were also performed using a specimen config-uration identical to that used in the dy-namic tests. The experimental results showed 1) friction stir welding reduces the yield stress of the weld metal to below that of the base metal; 2) both materials exhibit the strain rate effect, i.e.,the yield stress is higher under higher strain rates;and 3) the strain hardening appears to be similar for various strain rates.Introduction Friction stir welding (FSW) is a rela-t i vely new technique for joining alu-minum alloys (Ref. 1). Compared to tra-ditional fusion welding, friction stir welding is a solid-state joining process that does not melt the materials and has the potential to avoid significant ch a n g e s in microstructure and mechanical prop-erties. The FSW process provides a method for joining some aluminum al-l o ys that are not normally weldable. Fo r example, AA2024 and AA7075 are not recommended for arc welding, but the friction stir welding process can be used
to join these alloys without difficulty (Ref. 2).
Microstructure variation from the FSW process, as well as the development of the FSW process itself, has draw n much attention in past years (Refs. 3–10).However, the ultimate use of the weld is in structural application, which often in-volves the static, fatigue, dynamic or im-
pact type loading found in automotive and aerospace applications. We l d
strength, fracture and fatigue must be studied as well to ensure a safe and reli-
able operation of the welded structure.Recent studies along this direction in-clude Refs. 11–13. In many applications, the welded structure may be subjected to dy n a m i c load such as impact and explosion. It is,therefore, important to understand the mechanical properties of structural mate-rials at the high strain rate to which the components may be subjected during service. The objective of the current work is to evaluate changes in the compressive mechanical properties due to the friction stir welding process. Aluminum alloy s AA2024-T3 and AA7075-T7351 were studied. Samples were tested at a quasi-static rate using a standard hydraulic load frame and at high strain rates using a split Hopkinson pressure bar system. Results are reported in the form of stress-strain curves for different strain rates. Hardness values of the material before and after testing are also presented. The results can be used in evaluating the dynamic re-sponse of the FSW structures as well as in studying the material flow behavior of the friction stir welding process. Experiment Dynamic Tests The split Hopkinson pressure bar (SHPB) technique (Refs. 14–17) is one of the most popular experimental tech-niques for studying dynamic behavior of materials under high strain rate loading.The principle of this experimental tech-nique is based on the well-known one-dimensional theory of wave propagation in elastic bars and the interaction be-tween a stress pulse and a short cylindri-cal specimen, which is sandwiched be-tween the input and output bars. A
schematic illustration of the SHPB in this
study is shown in Fig. 1.
The typical SHPB setup consists of a gas gun, a striker, an input bar and an out-put bar. A gas gun accelerates the striker bar (projectile). The resulting impact with the input bar produces an elastic, com-p r e s s i ve pulse (incident pulse εi ). Th e elastic compressive pulse propagates down the input bar until it reaches the input bar/specimen interface. This com-pressive pulse then partially reflects back into the input bar (reflected pulse εr ) and partially transmits through the specimen into the output bar (transmitted pulse εt ).
These three stress pulses in the bars are recorded by strain gauges on the input
and output bars. The amplitude of the in-cident pulse depends on the striker ve-
locity. In addition, the length of the inci-
dent pulse is twice the time needed for an
elastic stress pulse to travel the length of the striker bar.Based on one-dimensional stress wave theory, the values of stress and strain in the specimen can be determined Effect of Friction Stir Welding on Dynamic Properties of AA2024-T3 and AA7075-T7351BY Y. J. CHAO, Y. WANG AND K. W. MILLER
Dynamic compressive flow behavior and its relation to yield stress and strain hardening were investigated
KEY WORDS Friction Stir Welding Hopkinson Bar Strain Rate Effect Aluminum Alloys Solid-State Welding Strain Hardening Y . J. CHAO , Y. WANG and K. W. MILLER are Professor and Research Associates, respec-tively, with the Department of Mechanical En-gineering, University of South Carolina, Co-lumbia, S.C.
by using records of strain gauges located on the input/output bars. The axial stress σs (t), strain ε
s (t), and strain ε
s (t) rate in the
specimen can be calculated as follow s (Ref. 17):(1)(2)(3)Where t = time; A = cross-sectional area of the bar; E = Young’s modulus of the bars; C 0= speed of the elastic longitudi-nal wave in the bar; L s = thickness of the
specimen; A s = cross-sectional area of the specimen; εi (t), εr (t), = incident and
reflected axial strain signals recorded by strain gauge on the input bar as a func-tion of time t; and εt (t) = transmitted axial
strain signal recorded by strain gauge on the output bar as a function of time t.Therefore, the constitutive relation-ship of the specimen material at a certain strain rate can be obtained using Equa-tion 1.A SHPB system was designed and built by the mechanics group in the De-partment of Mechanical Engineering,U n i versity of South Carolina. The steel input and output bars had lengths of 2.4 m (94.5 in.) and 1.2 m (47.2 in.), re-s p e c t i ve l y . They were instrumented with semiconductor strain gauges at two lo-cations. At each location, two gauges were oriented axially and were bonded to the opposite sides of the bar to cancel
a n y bending disturbance. The striker bar and input/output bars had the same di-
ameter 25.4 mm (1.0 in.) and were made
of O1 tool steel. The speed of the elastic
longitudinal wave of these steel bars wa s 5000 m/s (16,404 ft/s).
Typical recorded signals from the
s
t rain gauges are shown in Fig. 2. The in-
cident pulses were generated using a 287-
mm (11.3-in.) striker bar
with approxi-
mately 10 m/s (32.8 ft/s) impact speed.Different strain rate tests can be per-formed by using different length striker bars and generating different impact ve-locities. The strain rate variation from a typical test is shown in Fig. 3. The ave ra g e s t rain rate for this test of 1200/s is only an
˙ s t ()=C 0
L s i t ()?r t ()?t t ()[]s t ()=C 0
L s i t ()?r t ()?t t ()[]0∫d s t ()=EA
2A s i t ()+r t ()+t t ()[]
“e yeball estimate” because strain rate is not constant in this type of SHPB test. Specimens The alloys selected were AA2024-T3and AA7075-T7351. Two 9.5-mm-(0.374-in.-) thick plates for each type of the material were joined using friction stir welding on the Supermill-5VR mill at the University of South Carolina. Th e FSW tool is made of tool steel with a threaded pin. The outside diameter of the tool is 28 mm (1.1 in.) and the pin diam-eter and length are 10 mm and 7.5 mm (0.394 and 0.295 in.), respectively. The travel speed for welding is 113 mm/min (4.4 in./min) with a spindle speed of 215rpm. A schematic of the friction stir weld-ing process is shown in Fig. 4.After welding, cylindrical specimens were cut from the base metal and the weld zones of the aluminum plate. The orienta-tion of the cylindrical axis of the specimen was perpendicular to the aluminum plate,as shown schematically in Fig. 4. The spec-imen has a diameter of 20 mm (0.787 in.)and thickness of 9 mm (0.354 in). Quasistatic Test
To evaluate strain-rate sensitivity, qua-
sistatic compression tests were run on an MTS hydraulic load frame. A fixture was made for the compression tests, wh i c h were conducted with a crosshead veloc-ity producing a constant strain rate of 0.0001/s. Identical specimen configura-tions were used in both the dynamic and the quasistatic tests, allowing for a much more reliable comparison of data at var-ious strain rates.Microhardness Tests
To examine local variations in the me-chanical properties that occur in and around the friction stir weld zone, the hardness of the welding zone was tested with a Micromet microhardness tester. A Knoop indentor was used with a load of 200 g and dwell of 15 s. The Knoop hard-ness was measured across the centerline of the welded plate.All compression tests and hardness tests were performed at room tempera-ture, approximately 22°C.Results and Discussion The dynamic tests were performed at
s t r ain rates of 800/s and 1200/s for
AA2024-T3 and 500/s for AA7075-T7351. The experimentally determined compressive stress-strain relations at dif-ferent rates are shown in Figs. 5 and 6, re-spectively, for AA2024-T3 and AA7075-T7351. The comparison of the yield stress determined at 0.2% offset for different rates is listed in Table 1. Also, the yield stress at various strain rates are plotted vs.strain rate in log scale in Fig. 7.
It can be seen from Figs. 5 and 7 and Table 1 that both the AA2024-T3 base metal and the friction stir weld show an increase in yield stress with strain https://www.sodocs.net/doc/6e18871506.html,pared to quasistatic loading, the
yield stresses for the base metal and weld metal at 800/s increased 14% and 19%,r e s p e c t i ve l y . From 800/s to 1200/s, the yield stress for the base metal increased by 10%. However, the strain-rate sensi-tivity for weld metal is not as pronounced from 800/s to 1200/s. Under 1200/s dy-namic loading, the yield stress of the
weld metal is 16% less than that of the
base metal, and it is about 13% less in
yield stress under quasistatic loading.
The strain hardening after yielding for
both the base and FSW materials appear
to be very similar. It may be concluded
the effect of the FSW process on the me-chanical property of AA2024-T3 under both dynamic and quasistatic loading was approximately identical, i.e.,reduc-
ing the yielding stress by about 13% to
16% without changing the hardening be-
havior. This similarity in hardening could
be due to the base metal of AA 2024-T3
Fig. 5 — Stress-strain curves for AA2024-T3 at three strain rates.Fig. 6 — Stress-strain curves for AA7075-T7351 at two strain rates.Table 1 — Yield Stress of Different Materials at Different Strain Rates Strain Rate (1/s)Yield Stress σ0.2(GPa)AA2024-T3 base metal 1200/800/0.00010.420/0.381/0.335AA2024-T3 weld metal 1200/800/0.00010.352/0.346/0.290AA7075-T7351 base metal 500/0.00010.627/0.554AA7075-T7351 weld metal 500/0.00010.414/0.398
being stretched and naturally aged to sta-ble conditions. The FSW process relieved the stretch and eliminated the work hard-ening; consequently, parallel shift of the curves is seen in Fig. 5. For AA7075-T7351, an increase in yield stress of 13% from a strain rate of 0.0001/s to 500/s was found, as shown in Figs. 6 and 7 and Table 1. However, the yield stresses for weld material at quasi-static and dynamic loading rates are al-most identical, which means there is no apparent rate sensitivity up to 500/s in compression. Similar to AA2024-T3, the yield stresses for weld metal decrease at both high-rate and quasistatic loading compared to those of the base metal. Fur-thermore, the degree of decrease through friction stir welding at 500/s was higher than at 0.0001/s, as seen in Fig. 7. The s t r ain-hardening behavior of both the base metal and the weld metal appears to be very similar ,i.e.,seen as a parallel in-crease as the strain rate is increased.It should be mentioned the specimen (20 mm diameter and 9 mm thick) con-tains different microstructure regions g e n e r ated by the friction stir process.Therefore, data presented here are “lumped” material properties prototypi-cal for the weld as a whole, not for the in-dividual microstructure.The Knoop microhardness as a func-tion of distance from the centerline of the friction stir weld for AA2024-T3 and AA7075-T7351 is shown in Figs. 8 and 9,r e s p e c t i ve l y . Three regions are obv i o u s from the hardness distribution in Figs. 8and 9: 1) the central part of the weld cor-responds to the fully plasticized region of the FSW weld; 2) the heat-affected zone has the lowest hard-
ness; and 3) the base
metal has the highest
hardness. The va r i a -
tion of the hardness
from base metal to
weld metal is larger
for AA7075-T7351
than AA2024-T3,
which correlates with
the yield stress results
shown in Fig. 7. The
base metal on two
sides of the FSW weld
s h o w a slight differ-
ence in hardness,
possibly due to the
asymmetric nature of
the process (tra i l i n g
vs. leading side).
The hardness of the
samples (AA2024-T3
weld metal at 1200/s;
AA7075-T7351 weld
metal at 500/s) used
in the dynamic test
was also measured after the tests. As shown in Figs. 8 and 9, dynamic loading
increased the hardness of the weld and,accordingly, the yield stress. This is obvi-ously due to the work hardening of the material, which has had a large perma-nent plastic strain.Note the tests were performed approx-imately two months after the FSW wa s made. This time is probably sufficient for AA2024-T3 to stabilize, but this is not true for AA7075-T7351. Both the base metal and the weld are expected to age continu-ously for AA7075-T7351; thus, higher strength may be obtained later.Conclusions
A split Hopkinson pressure bar or Ko
l-s ky bar system typically used to determine
the dynamic behavior of materials was in-
troduced. Dynamic, compressive stress-s t rain curves were obtained for AA2024-T3 and AA7075-T7351 aluminum alloy s ,as well as their weld material produced by the FSW process. The experimental results indicated the follow i n g :
1) Yield stresses of both base and fric-tion stir weld material of AA2024-T3 ex-hibited rate sensitiv i t y . In addition,AA7075-T7351 base metal had some
rate dependence. However, no rate effect was found for AA7075-T7351 friction stir weld material up to the strain rate of 500/s.2) Friction stir welding reduced the yield stress of both AA2024-T3 and AA7075-T7351 under both high stra i n -rate and quasistatic loading conditions. 3) Strain hardening is similar for both materials at various strain rates.The results reported in the current paper can have two applications. One is to aid in process modeling – e.g ., mater-ial flow characterization. Recent studies at the University of South Carolina (Ref.18) indicate the strain rate near the vicin-ity of the tool pin can be as high as 10001/s. The results in this paper provide pre-liminary technical information for such a modeling effort. It is, how e v e r , under-stood high material strain rate occurs at e l e v ated temperature during welding.Therefore, our future work will study ma-terial rate data, similar to that reported here but at high temperatures for friction stir welding process modeling. The immediate and second applica-tion of the results reported in this paper are for structural performance, e.g .,load-carrying capability, fracture and reliabil-ity of the weld. As mentioned in the in-troduction section, welded structures m a y be subjected to dynamic impact load. As such, high strain (loading) rate behavior of the weld, such as the data re-ported here, is essential in modeling and understanding the dynamic response of the welded structures. Acknowledgments The authors are grateful for labora t o r y assistance from Daniel Wilhelm of the U n i versity of South Carolina. Funding from the National Science Fo u n d a t i o n through NSF/EPSCoR coopera t ive agree-ment #EPS-9630167 and the Air Fo rce Re-s e a rch Lab/Materials Lab (AFRL/ML), with D r. Kumar Jata, is greatly appreciated.References 1. Dawes, C. T., and Thomas, W. M. 1996.Friction stir process welds aluminum alloys: a new friction welding technique allows easy welding of normally difficult-to-join materials.Welding Journal 75(3): 41.2. ASM Handbook, Vol. 6. 1983. ASM In-ternational, Materials Park, Ohio, pp. 373.3. Rhodes, C. G. 1997. Effects of friction stir welding on microstructure of 7075 alu-minum. Scripta Materialia 36(1): 69–75.4. Flores, O. V., Kennedy, C., Murr, L. E.,Brown, D., Pappu, S., Nowak, B. M., and Mc-Clure, J. C. 1998. Microstructural issues in a f r i c t i o n -s t i r -welded aluminum alloy. S c r i p t a Materialia 38(5): 703–708.5. Frigaard, G., and Midling, O. T. 2001. A process model for friction stir welding of age hardening aluminum alloys. Metallurgical and Materials Transactions A 32A(5): 1189–1200.6. Mahoney, M. W., Rhodes, C. G., Flintoff,J. G., Spurling, R. A., and Bingel, W. H. 1998.Properties of friction-stir-welded 7075 T651aluminum. Metallurgical and Materials T rans-actions A 29A(7): 1955–1964. 7. Rhodes, C. G., Mahoney, M. W., Bingel,W. H., Spurling, R. A., and Bampton, C. C.1997. Effects of friction stir welding on mi-crostructure of 7075 aluminum. Scripta Mate-rialia 36( 1): 69–75.
8. Benavides, S., Li, Y., Murr, L. E., Brown,
D., and McClure, J. C., 1999. Low-tempera-
ture friction stir welding of 2024 aluminum.
Scripta Materialia
41(8): 809–815. 9. Li, Y ., Murr, L. E., and
McClure, J. C.1999. Flow visualization and residual mi-
crostructures associated with the friction stir welding of 2024 aluminum to 6061 alu-
minum. Materials Science and Engineering A
271(1-2): 213-223.10. Chao, Y. J., Qi, X. H. 1999. Thermal and thermo-mechanical modeling of friction stir welding of aluminum alloy 6061-T6. Jour-
nal of Material Processing and Manufacturing 7(2): 215–233.11. Jata, K. V., Sankaran, K. K., and Ruschau, J. J. 2000. Friction stir welding effects
on microstructure and fatigue of aluminum
Alloy 7050-T7451. Metallurgical and Materi-als Transactions A 31A(9): 2181–2192.
12. Hu, W. S., Meletis, E. I. 2000. Corro-sion and environment-assisted cra c king be-havior of friction stir welded Al 2195 and Al 2219 alloys. Material Science Forum , pp. 331-333: 1683-1688, Part 1–3.
13. Haagensen, P . J., Midling, O, T. and Ranes, M. 1996. Fatigue performance of fric-tion stir butt welds in a 6000 series aluminum a l l o y. International Journal of Fa t i g u e 1 8(7):508. 14. Kolsk y, H. 1949. An investigation of the m e c hanical properties of materials at ve r y high rates of loading. Proc. Phys. Soc. (Lon-don) B62: 676–700.15. Lindholm, U. S. 1964. Some experi-ments with the Split Hopkinson Pressure Bar.J. Mech. Phys. Solids 2: 317–335.16. Nicholas, T. 1992. Impact Dynamics ,eds. Zukas, J. A., Nicholas, T., Swift, H. L.,Greszczuk, L. B., and Curran, D. R. Krieger,Malabar, Fla.17. ASM Handbook . 1985. High strain rate testing. ASM International, Materials Pa r k ,Ohio, 8:198.18. Private communication with Professor Anthony P. Reynolds, University of South Car-olina, 2001.
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英语造句
一般过去式 时间状语：yesterday just now (刚刚) the day before three days ag0 a week ago in 1880 last month last year 1. I was in the classroom yesterday. I was not in the classroom yesterday. Were you in the classroom yesterday. 2. They went to see the film the day before. Did they go to see the film the day before. They did go to see the film the day before. 3. The man beat his wife yesterday. The man didn’t beat his wife yesterday. 4. I was a high student three years ago. 5. She became a teacher in 2009. 6. They began to study english a week ago 7. My mother brought a book from Canada last year. 8.My parents build a house to me four years ago . 9.He was husband ago. She was a cooker last mouth. My father was in the Xinjiang half a year ago. 10.My grandfather was a famer six years ago. 11.He burned in 1991
学生造句--Unit 1
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英语句子结构和造句
高中英语~词性~句子成分~语法构成 第一章节：英语句子中的词性 1.名词：n. 名词是指事物的名称，在句子中主要作主语.宾语.表语.同位语。 2.形容词;adj. 形容词是指对名词进行修饰~限定~描述~的成份，主要作定语.表语.。形容词在汉语中是（的）.其标志是: ous. Al .ful .ive。. 3.动词：vt. 动词是指主语发出的一个动作，一般用来作谓语。 4.副词：adv. 副词是指表示动作发生的地点. 时间. 条件. 方式. 原因. 目的. 结果.伴随让步. 一般用来修饰动词. 形容词。副词在汉语中是（地）.其标志是：ly。 5.代词：pron. 代词是指用来代替名词的词，名词所能担任的作用，代词也同样.代词主要用来作主语. 宾语. 表语. 同位语。 6.介词：prep.介词是指表示动词和名次关系的词，例如：in on at of about with for to。其特征：
介词后的动词要用—ing形式。介词加代词时，代词要用宾格。例如：give up her（him）这种形式是正确的，而give up she（he）这种形式是错误的。 7.冠词：冠词是指修饰名词，表名词泛指或特指。冠词有a an the 。 8.叹词：叹词表示一种语气。例如：OH. Ya 等 9.连词：连词是指连接两个并列的成分，这两个并列的成分可以是两个词也可以是两个句子。例如：and but or so 。 10.数词：数词是指表示数量关系词，一般分为基数词和序数词 第二章节：英语句子成分 主语：动作的发出者，一般放在动词前或句首。由名词. 代词. 数词. 不定时. 动名词. 或从句充当。 谓语：指主语发出来的动作，只能由动词充当，一般紧跟在主语后面。 宾语：指动作的承受着，一般由代词. 名词. 数词. 不定时. 动名词. 或从句充当. 介词后面的成分也叫介词宾语。 定语：只对名词起限定修饰的成分，一般由形容
六级单词解析造句记忆MNO
M A: Has the case been closed yet? B: No, the magistrate still needs to decide the outcome. magistrate n.地方行政官，地方法官，治安官 A: I am unable to read the small print in the book. B: It seems you need to magnify it. magnify vt.１．放大，扩大；２．夸大，夸张 A: That was a terrible storm. B: Indeed, but it is too early to determine the magnitude of the damage. magnitude n.１．重要性，重大；２．巨大，广大 A: A young fair maiden like you shouldn’t be single. B: That is because I am a young fair independent maiden. maiden n.少女，年轻姑娘，未婚女子 a.首次的，初次的 A: You look majestic sitting on that high chair. B: Yes, I am pretending to be the king! majestic a.雄伟的，壮丽的，庄严的，高贵的 A: Please cook me dinner now. B: Yes, your majesty, I’m at your service. majesty n.１．［Ｍ－］陛下（对帝王，王后的尊称）；２．雄伟，壮丽，庄严 A: Doctor, I traveled to Africa and I think I caught malaria. B: Did you take any medicine as a precaution? malaria n.疟疾 A: I hate you! B: Why are you so full of malice? malice n.恶意，怨恨 A: I’m afraid that the test results have come back and your lump is malignant. B: That means it’s serious, doesn’t it, doctor? malignant a.１．恶性的，致命的；２．恶意的，恶毒的 A: I’m going shopping in the mall this afternoon, want to join me? B: No, thanks, I have plans already. mall n.（由许多商店组成的）购物中心 A: That child looks very unhealthy. B: Yes, he does not have enough to eat. He is suffering from malnutrition.
base on的例句
意见应以事实为根据. 3 来自辞典例句 192. The bombers swooped ( down ) onthe air base. 轰炸机 突袭 空军基地. 来自辞典例句 193. He mounted their engines on a rubber base. 他把他们的发动机装在一个橡胶垫座上. 14 来自辞典例句 194. The column stands on a narrow base. 柱子竖立在狭窄的地基上. 14 来自辞典例句 195. When one stretched it, it looked like grey flakes on the carvas base. 你要是把它摊直, 看上去就象好一些灰色的粉片落在帆布底子上. 18 来自辞典例句 196. Economic growth and human well - being depend on the natural resource base that supports all living systems. 经济增长和人类的福利依赖于支持所有生命系统的自然资源. 12 1 来自辞典例句 197. The base was just a smudge onthe untouched hundred - mile coast of Manila Bay. 那基地只是马尼拉湾一百英里长安然无恙的海岸线上一个硝烟滚滚的污点. 6 来自辞典例句 198. You can't base an operation on the presumption that miracles are going to happen. 你不能把行动计划建筑在可能出现奇迹的假想基础上.
英语造句大全
英语造句大全English sentence 在句子中，更好的记忆单词！ 1、(1)、able adj. 能 句子：We are able to live under the sea in the future. (2)、ability n. 能力 句子：Most school care for children of different abilities. (3)、enable v. 使。。。能句子：This pass enables me to travel half-price on trains. 2、(1)、accurate adj. 精确的句子：We must have the accurate calculation. (2)、accurately adv. 精确地 句子：His calculation is accurately. 3、(1)、act v. 扮演 句子：He act the interesting character. （2）、actor n. 演员 句子：He was a famous actor. (3)、actress n. 女演员 句子：She was a famous actress. (4)、active adj. 积极的 句子：He is an active boy. 4、add v. 加 句子：He adds a little sugar in the milk. 5、advantage n. 优势 句子：His advantage is fight. 6、age 年龄n. 句子：His age is 15. 7、amusing 娱人的adj. 句子：This story is amusing. 8、angry 生气的adj. 句子：He is angry. 9、America 美国n.
(完整版)主谓造句
主语+谓语 1. 理解主谓结构 1) The students arrived. The students arrived at the park. 2) They are listening. They are listening to the music. 3) The disaster happened. 2．体会状语的位置 1) Tom always works hard. 2) Sometimes I go to the park at weekends.. 3) The girl cries very often. 4) We seldom come here. The disaster happened to the poor family. 3. 多个状语的排列次序 1) He works. 2) He works hard. 3) He always works hard. 4) He always works hard in the company. 5) He always works hard in the company recently. 6) He always works hard in the company recently because he wants to get promoted. 4. 写作常用不及物动词 1. ache My head aches. I’m aching all over. 2. agree agree with sb. about sth. agree to do sth. 3. apologize to sb. for sth. 4. appear (at the meeting, on the screen) 5. arrive at / in 6. belong to 7. chat with sb. about sth. 8. come (to …) 9. cry 10. dance 11. depend on /upon 12. die 13. fall 14. go to … 15. graduate from 16. … happen 17. laugh 18. listen to... 19. live 20. rise 21. sit 22. smile 23. swim 24. stay (at home / in a hotel) 25. work 26. wait for 汉译英： 1.昨天我去了电影院。 2.我能用英语跟外国人自由交谈。 3.晚上7点我们到达了机场。 4.暑假就要到了。 5.现在很多老人独自居住。 6.老师同意了。 7.刚才发生了一场车祸。 8.课上我们应该认真听讲。9. 我们的态度很重要。 10. 能否成功取决于你的态度。 11. 能取得多大进步取决于你付出多少努力。 12. 这个木桶能盛多少水取决于最短的一块板子的长度。
初中英语造句
【it's time to和it's time for】 ——————这其实是一个句型,只不过后面要跟不同的东西. ——————It's time to跟的是不定式（to do）.也就是说,要跟一个动词,意思是“到做某事的时候了”.如： It's time to go home. It's time to tell him the truth. ——————It's time for 跟的是名词.也就是说,不能跟动词.如： It's time for lunch.(没必要说It's time to have lunch) It's time for class.(没必要说It's time to begin the class.) They can't wait to see you Please ask liming to study tonight. Please ask liming not to play computer games tonight. Don’t make/let me to smoke I can hear/see you dance at the stage You had better go to bed early. You had better not watch tv It’s better to go to bed early It’s best to run in the morning I am enjoy running with music. With 表伴随听音乐 I already finish studying You should keep working. You should keep on studying English Keep calm and carry on 保持冷静继续前行二战开始前英国皇家政府制造的海报名字 I have to go on studying I feel like I am flying I have to stop playing computer games and stop to go home now I forget/remember to finish my homework. I forget/remember cleaning the classroom We keep/percent/stop him from eating more chips I prefer orange to apple I prefer to walk rather than run I used to sing when I was young What’s wrong with you There have nothing to do with you I am so busy studying You are too young to na?ve I am so tired that I have to go to bed early
The Kite Runner-美句摘抄及造句
《The Kite Runner》追风筝的人--------------------------------美句摘抄 1.I can still see Hassan up on that tree, sunlight flickering through the leaves on his almost perfectly round face, a face like a Chinese doll chiseled from hardwood: his flat, broad nose and slanting, narrow eyes like bamboo leaves, eyes that looked, depending on the light, gold, green even sapphire 翻译：我依然能记得哈桑坐在树上的样子，阳光穿过叶子，照着他那浑圆的脸庞。他的脸很像木头刻成的中国娃娃，鼻子大而扁平，双眼眯斜如同竹叶，在不同光线下会显现出金色、绿色，甚至是宝石蓝。 E.g.: A shadow of disquiet flickering over his face. 2.Never told that the mirror, like shooting walnuts at the neighbor's dog, was always my idea. 翻译：从来不提镜子、用胡桃射狗其实都是我的鬼主意。E.g.:His secret died with him, for he never told anyone. 3.We would sit across from each other on a pair of high
翻译加造句
一、翻译 1. The idea of consciously seeking out a special title was new to me., but not without appeal. 让我自己挑选自己最喜欢的书籍这个有意思的想法真的对我具有吸引力。 2.I was plunged into the aching tragedy of the Holocaust, the extraordinary clash of good, represented by the one decent man, and evil. 我陷入到大屠杀悲剧的痛苦之中，一个体面的人所代表的善与恶的猛烈冲击之中。 3.I was astonished by the the great power a novel could contain. I lacked the vocabulary to translate my feelings into words. 我被这部小说所包含的巨大能量感到震惊。我无法用语言来表达我的感情（心情）。 4，make sth. long to short长话短说 5.I learned that summer that reading was not the innocent(简单的) pastime(消遣) I have assumed it to be., not a breezy, instantly forgettable escape in the hammock(吊床)，( though I’ ve enjoyed many of those too ). I discovered that a book, if it arrives at the right moment, in the proper season, will change the course of all that follows. 那年夏天，我懂得了读书不是我认为的简单的娱乐消遣，也不只是躺在吊床上，一阵风吹过就忘记的消遣。我发现如果在适宜的时间、合适的季节读一本书的话，他将能改变一个人以后的人生道路。 二、词组造句 1. on purpose 特意，故意 This is especially true here, and it was ~. (这一点在这里尤其准确，并且他是故意的) 2.think up 虚构，编造，想出 She has thought up a good idea. 她想出了一个好的主意。 His story was thought up. 他的故事是编出来的。 3. in the meantime 与此同时 助记：in advance 事前in the meantime 与此同时in place 适当地... In the meantime, what can you do? 在这期间您能做什么呢？ In the meantime, we may not know how it works, but we know that it works. 在此期间，我们不知道它是如何工作的，但我们知道，它的确在发挥作用。 4.as though 好像，仿佛 It sounds as though you enjoyed Great wall. 这听起来好像你喜欢长城。 5. plunge into 使陷入 He plunged the room into darkness by switching off the light. 他把灯一关，房
改写句子练习2标准答案
The effective sentences:(improve the sentences!) 1.She hopes to spend this holiday either in Shanghai or in Suzhou. 2.Showing/to show sincerity and to keep/keeping promises are the basic requirements of a real friend. 3.I want to know the space of this house and when it was built. I want to know how big this house is and when it was built. I want to know the space of this house and the building time of the house. 4.In the past ten years,Mr.Smith has been a waiter,a tour guide,and taught English. In the past ten years,Mr.Smith has been a waiter,a tour guide,and an English teacher. 5.They are sweeping the floor wearing masks. They are sweeping the floor by wearing masks. wearing masks,They are sweeping the floor. 6.the drivers are told to drive carefully on the radio. the drivers are told on the radio to drive carefully 7.I almost spent two hours on this exercises. I spent almost two hours on this exercises. 8.Checking carefully,a serious mistake was found in the design. Checking carefully,I found a serious mistake in the design.
用以下短语造句
M1 U1 一. 把下列短语填入每个句子的空白处（注意所填短语的形式变化）： add up (to) be concerned about go through set down a series of on purpose in order to according to get along with fall in love (with) join in have got to hide away face to face 1 We’ve chatted online for some time but we have never met ___________. 2 It is nearly 11 o’clock yet he is not back. His mother ____________ him. 3 The Lius ___________ hard times before liberation. 4 ____________ get a good mark I worked very hard before the exam. 5 I think the window was broken ___________ by someone. 6 You should ___________ the language points on the blackboard. They are useful. 7 They met at Tom’s party and later on ____________ with each other. 8 You can find ____________ English reading materials in the school library. 9 I am easy to be with and _____________my classmates pretty well. 10 They __________ in a small village so that they might not be found. 11 Which of the following statements is not right ____________ the above passage? 12 It’s getting dark. I ___________ be off now. 13 More than 1,000 workers ___________ the general strike last week. 14 All her earnings _____________ about 3,000 yuan per month. 二.用以下短语造句： 1.go through 2. no longer/ not… any longer 3. on purpose 4. calm… down 5. happen to 6. set down 7. wonder if 三. 翻译： 1.曾经有段时间，我对学习丧失了兴趣。（there was a time when…） 2. 这是我第一次和她交流。（It is/was the first time that …注意时态） 3.他昨天公园里遇到的是他的一个老朋友。（强调句） 4. 他是在知道真相之后才意识到错怪女儿了。（强调句） M 1 U 2 一. 把下列短语填入每个句子的空白处（注意所填短语的形式变化）： play a …role (in) because of come up such as even if play a …part (in) 1 Dujiangyan(都江堰) is still ___________in irrigation(灌溉) today. 2 That question ___________ at yesterday’s meeting. 3 Karl Marx could speak a few foreign languages, _________Russian and English. 4 You must ask for leave first __________ you have something very important. 5 The media _________ major ________ in influencing people’s opinion s. 6 _________ years of hard work she looked like a woman in her fifties. 二.用以下短语造句： 1.make (good/full) use of 2. play a(n) important role in 3. even if 4. believe it or not 5. such as 6. because of
英语造句
English sentence 1、(1)、able adj. 能 句子：We are able to live under the sea in the future. (2)、ability n. 能力 句子：Most school care for children of different abilities. (3)、enable v. 使。。。能 句子：This pass enables me to travel half-price on trains. 2、(1)、accurate adj. 精确的 句子：We must have the accurate calculation. (2)、accurately adv. 精确地 句子：His calculation is accurately. 3、(1)、act v. 扮演 句子：He act the interesting character.（2）、actor n. 演员 句子：He was a famous actor. (3)、actress n. 女演员 句子：She was a famous actress. (4)、active adj. 积极的 句子：He is an active boy. 4、add v. 加 句子：He adds a little sugar in the milk. 5、advantage n. 优势 句子：His advantage is fight. 6、age 年龄n. 句子：His age is 15. 7、amusing 娱人的adj. 句子：This story is amusing. 8、angry 生气的adj. 句子：He is angry. 9、America 美国n. 句子：He is in America. 10、appear 出现v. He appears in this place. 11. artist 艺术家n. He is an artist. 12. attract 吸引 He attracts the dog. 13. Australia 澳大利亚 He is in Australia. 14.base 基地 She is in the base now. 15.basket 篮子 His basket is nice. 16.beautiful 美丽的 She is very beautiful. 17.begin 开始 He begins writing. 18.black 黑色的 He is black. 19.bright 明亮的 His eyes are bright. 20.good 好的 He is good at basketball. 21.British 英国人 He is British. 22.building 建造物 The building is highest in this city 23.busy 忙的 He is busy now. 24.calculate 计算 He calculates this test well. 25.Canada 加拿大 He borns in Canada. 26.care 照顾 He cared she yesterday. 27.certain 无疑的 They are certain to succeed. 28.change 改变 He changes the system. 29.chemical 化学药品