The room is dirty. It ____ cleaned.
A. can‘t be
B. couldn’t be
C. mustn't be
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Mary ____ the exam if she studied harder.
A. can have passed
B. could have passed
C. couldn't have passed
An Englishman who ____not speak Chinese is going to live in China.
A. must
B. could
C. can
It ____ be hot in the summer.
A. can
B. couldn’t
C. can’t
–Who is the man over there? Is it Mr. Li?
A. No, it ______ be him. Mr. Li is much taller.
B. mustn’t
C. could not
D. can’t