摘要：Before the first non?stop flight made in 1949, it necessary for all planes to land for refueling. A.would be B.has been C.had been D.would have been
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Before the first non-stop flight made in 1949, it ________ necessary for all planes to land for refueling.
[ ]
A．would be
B．has been
C．had been
D．would have been
11.Before the first non-stop flight made in 1949, it ________ necessary for all planes to land for refueling.
A. would be B. has been C. had been D. would have been
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11.Before the first
non-stop flight made in 1949, it ________ necessary for all planes to land for
refueling.
A. would be B. has been C. had been D. would have been
查看习题详情和答案>>