John's score on the test is the highest in the class; he____ last night.
A. should study
B. should have studied
C. must have studied
D. must have to study
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The room is in a terrible mess; it ____cleaned. (CET-4, 1996,6)
A. can't have been
B. shouldn't have been
C. mustn't have been
D. wouldn't have been
Nobody knows how people first came to these islands. They ____ from South America on rafts.
A. must have sailed
B. can sail
C. might have sailed
D. should have sailed
Mary was not in her bedroom yesterday afternoon. She ____ in her classroom.
A. should have been
B. must have been
C. must be
D. should be
Bob said he was going to join our club but he didn't. He ____ his mind.
A. can't have changed
B. wouldn't have changed
C. must have changed
D. shouldn't have changed