第1题,She decided to devote herself _______ the problem of old age.
第2题,This is the hotel _______last month.
A、which they stayed
B、at that they stayed
C、where they stayed at
D、where they stayed
第3题,Have you read a newspaper report probing ______ the activities of drug dealers?
第4题,His business was very successful, but it was at the ________ of his family life.
第5题,He has _______ much time and energy for his invention.