How long 与 How many hours 有什么区别

① Emma watches television for about twenty hours a week.

② Emma watches televisionfor about twenty hoursa week.

请问对这两句的提问到底是How long a week...? 还是How many hours a week...?

① Emma watches television for about twenty hours a week.

② Emma watches televisionfor about twenty hoursa week.

请问对这两句的提问到底是How long a week...? 还是How many hours a week...?

【答】第2句的划线不正确。for 跟hours 有关，about twenty 是定语，应在about twenty 下面划线。改为：

② Emma watches televisionfor about twentyhoursa week.

那样，这两句的提问分别是：

① How long does Emma watch television a week?

② For how many hours does Emma watch television a week?