1.The millions of calculations involved, had they been done by hand, ___ all practical value by the time they were finished.
C.would have lost
D.should have lost
2.___ he has limited technical knowledge, the old worker has a lot of experience.
3.It worried her a bit ___her hair was turning grey.
4.The _______ work continued for more than a week but there was still no sign of the missing boy.
5.Sixty percent of the work___
A.have been done
B.had been done
C.has been done
6.His parents wouldn’t let him marry anyone ___ family was poor .
7.You ___ him so closely; you should have kept your distance.
C.couldn’t’ have been following
D.shouldn’t have been following
8.___ in the United States, St. Louis has now become the 24th largest city.
A.The fourth biggest city it was
B.Once the fourth biggest city
C.Being the fourth biggest city
D.It was once the fourth biggest city
9.___ we can’t get seems better than ___ we have.
10.Eye contact is important because wrong contact may create a communication ___.
11.What worried me most was ___ to go abroad alone.
A.my not allowing
B.having not allowed
C.my being not allowed
D.my not being allowed
12.I think I was at school, ___ I was staying with friends during the vacation when I heard the news.
13.There was a big hole in the road which ________ the traffic.
14.She wrote a letter ___ black ink.
15.The professor could hardly find sufficient grounds ___ his arguments in favour of the new theory.
A.to be based on
B.to base on
C.which to base on
D.on which to base
16.He is a man ___ we can learn very much.
17."What do you hear from your family?" "Oh, the news _______ pretty good. "
18.He has resigned and will ___charge of his office today.
19.In the dark street, there wasn’t a single person ___ she could turn for help.
20.Robert is good at languages, ____ we all know.