I didn’t go to the post office, so my wallet can’t _________ at the post office.
A. have been lost
B. has been lost
C. have being lost
D. has being lost
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Food ________ in a cool place in summer.
A. must keep
B. mustn’t keep
C. must be kept
D. mustn’t be kept
How _________ this word pronounced?
A. was
B. has been
C. is
D. had been
It is impossible for lost money _________ by ourselves.
A. to be found
B. be found
C. to being found
D. being found
机器的主要作用是利用机械能做功或实现能量的转换
A. 对
B. 错
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