1. —Can children swim in this pool? —Yes. However, they ____ never do so alone.
A.may B.need C.could D.should
C为什么不行?
10.You have no idea ____ those days.
A.that we were how busy B.how busy were we
C.that how busy we were D.how busy we were
C为什么不行?
16.--Jack, how did it_ that you made so many mistakes in your homework? --Well; I have no idea, either.
A.come about B.occur to C.bring about D.happened
这几个词有什么区别?
18.When the others had gone, he ___ and put back the furniture.
A.remained B.left C.kept D.stayed
能不能分析一下呀?