If the work （） completed by the end of the month is delayed, the construction company will be fined.

单项选择题It is most desirable that he （） hands with us in our common effort.

A. join
B. joined
C. will join
D. be joined

单项选择题But that he saw it, he （） it.

A. can’t believe
B. could not believe
C. did not believe
D. could not have believed