which grade还是what grade
问题描述：
which grade还是what grade
Daniel and Sam are in Grade Seven.
对Seven 部分提问
____ ___are Daniel and Sam in?
Sandy plays football once a week
对once a week 部分提问
____ _____does Sandy play football?
答
Which grade 和What grade 都可以,只是意思有点不一样,一个是他们是什么级别,一个是他们是哪个级别.两个都说得通
第二个是How often,直译：多么经常.也就是问频率