The revolution of machinery could __________without a new source of both movable and constant power in the new century.

2023-05-26

A. be born
B. not have been born
C. have been born
D. have born

参考答案:B

考查虚拟语气。当从句中出现without/ but for 等词时,主句要用虚拟语气,根据句意,如果没有新能源,机械改革不会诞生,再结合整句话的时态,应该用could not have been born。