2. 外语
  3. Before the first non-stop flight made in 1949, it______necessary for all planes to land for refueling.

Before the first non-stop flight made in 1949, it______necessary for all planes to land for refueling.

admin2019-11-28  50
问题 Before the first non-stop flight made in 1949, it______necessary for all planes to land for refueling.
选项 A、would be
B、has been
C、had been
D、would have been
答案C
解析 由before引导的时间状语表示过去，所以主句应该采用过去完成时，表示“过去的过去”。
转载请注明原文地址:https://kaotiyun.com/show/K5RK777K
0

专业英语四级

相关试题推荐
随机试题
最新回复(0)