题目内容：

The children should be taught when the house caught fire.为什么填what to do,不填how to do it?
The children should be taught--------- when the house caught fire.

优质解答

此话翻译为：当房屋起火时孩子应该让孩子知道该做什么事.
此处用what to do表示“做什么”的意思.how to do it中it 指代不清,所以不填.