题目内容
（请给出正确答案）
[主观题]
______, many problems of space flight could not be solved now.A．If electronic computers wo
______, many problems of space flight could not be solved now.
A．If electronic computers would not have been invented
B．Had electronic computers not invented
C．Had electronic computers not been invented
D．If electronic computers were not invented
提问人：网友wly1230
发布时间：2022-01-07
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