An earthquake may hit some places at any time.Do you know what to do in an earthquake?为什么

问题描述:

An earthquake may hit some places at any time.Do you know what to do in an earthquake?为什么
用at和what?为什么不是in和how呢?

at any time 是固定短语,"在任何时候/随时",不能换成in.
因为do是及物动词,必须跟宾语,而how是副词,不能作宾语,因此只能用what 来作宾语.
这种情况就可用how .
Do you know how to do the homework