She must be studying in the library.

她一定正在图书馆学习。

youdao

Mary studies hard. Now she can't (couldn't) be sleeping. She must be studying.

玛丽学习努力，现在她不可能在睡觉，她肯定正在学习。

youdao

Mary studies hard. Now she can't (couldn't) be sleeping. She must be studying.

玛丽学习努力，现在她不可能在睡觉，她肯定正在学习。

youdao