31.-What are on show in the museum?-Some pictures ____ by middle-school students.
The task _______ in an hour. Then we can go home and have a good rest.
Many accidents________ by careless drivers last year.
Studying in groups is necessary_____ you want to do well in school.
You can hardly imagine the ______ they went ______.
---He didn’t go to the concert yesterday, did he? ---_______, he was studying for the tests all day.