Before the first nonstop 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
Before the first nonstop flight made in 1949, it necessary for all planes to land for refu
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解决时间 2021-01-03 22:21
- 提问者网友：像風在裏
- 2021-01-03 16:31
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- 五星知识达人网友：雪起风沙痕
- 2021-01-03 17:27
A. would beB. has been(答案→)C. had beenD. would have been解析：考查时态：句意：在1949年世界上首次不间断飞行之前, 所有飞机有必要的降落加油。说明“有必要”是在1949年之前，用过去完成时，选C。
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- 1楼网友：孤独的牧羊人
- 2021-01-03 18:53
好好学习下
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