她不是在图书馆，就是在教室里。

She is either in the library or in the classroom.

youdao

他一定是在图书馆。他不可能在教室里。

He must be in the library. He can't be in the classroom.

youdao

他一定是在图书馆。他不可能在教室里。

He must be in the library. He can't be in the classroom.

youdao