超星 - Can & Could - 查题吧

单选题

At that time we thought the story_____ not be true.

A. could
B. must
C. can

单选题

You___ the work better in the future.

A. could did
B. can does
C. could do

单选题

The room is dirty. It ____ cleaned.

A. can‘t be
B. couldn’t be
C. mustn't be

单选题

Mary ____ the exam if she studied harder.

A. can have passed
B. could have passed
C. couldn't have passed

单选题

An Englishman who ____not speak Chinese is going to live in China.

A. must
B. could
C. can

2