The science of computer, _____rapid progress has been made in recent years, is the most important of all science.
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.
I have been to Shanghai. I______ there last month.