题目内容：

1.As a teacher, she can’t have any students _____________________ cheating in the exam.

2.China has a population of 1.4 billion, with the aged _______________ 15.5%.

3.He wore a puzzled look on his face, _________that he didn’t quite follow what she said.

4.To form a music band, they advertised for people __________________singing and performing.

5.His mind wandered from time to time in class. He should _______________ to his lessons and taking notes.

6.Not knowing about each other, they had a hard time in________________ to carry out the research at the beginning.

7.You are promised to get extra pay for extra work, _______________ your work done.

8.He_____________ the responsibility for collecting evidence for the trial without giving it a second thought.