问题

The eighteenth and nineteenth centuries _____ the widespread use of electricity and the birth of the steam engine , leading to the development of factories and cities.

A:watched
B:observed
C:saw
D:showed

正确答案是：

同类题型

An opinion is _____ someone believes is true but has not been proved.

We found it difficult _______ there ontime.

It is sunny outside, we decide____hiking.

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Diaoyu Island belongs to China.—Surely it does! We Chinese will never it up.