句型转换（每空一词）。

1. They have to stay at school all day.（对画线部分提问）

                     they have to        all day?

2. Today is Tuesday the 20th.（对画线部分提问）

                     ？

3. Let's go to the movies.（改为同义句）

                     going to the movies?

4. Can you come to my house for dinner?（作肯定回答）

    ___    _，         love to.

5. Li Lei has to babysit his sister.（改为一般疑问句）

             Li Lei        to babysit his sister?

三相电动机的极数是指电动机定子绕组通入三相电时（）。

A、三相绕组产生会成磁场N、S极的总数；

B、每相产主磁场N极的个数；

C、能产生磁场N极的个数．