My brother thought it was a UFO. But I'm not really sure. It ____ a military plane or a weather balloon.
A. might have been
B. might be
C. must be
D. can be
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Tom isn't answering his phone. He ______ shopping,or perhaps he's asleep.
A. can have gone
B. might have gone
C. has gone
D. might be going
I wonder why Tom isn't at work today. I suppose he ___ ill.
A. must be
B. mustn't be
C. can be
D. needn't be
Did she see you?No, she ____me.
A. can't see
B. mustn't have seen
C. mustn't see
D. can't have seen
The phone rang, but I didn't hear it. I ______ asleep.
A. must be
B. might be
C. must have been
D. can't be
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