题目内容:
The revolution of machinery could __________without a new source of both movable and constant power in the new century.
A. be born B. not have been born C. have been born D. have born
参考答案:
答案解析:
The revolution of machinery could __________without a new source of both movable and constant power in the new century.
A. be born B. not have been born C. have been born D. have born