解释the teachers are doing what they can to teach students

这是什么用法？

can＋to do？

这个句子应该这样断句

the teachers are doing what they can∕ to teach students

what they can是doing的宾语从句，意思是老师做一切他们能做的事

 to teach students老师做事的目的——教学生

状语从句

你误会这道题了。这里can 和to do 是不能放在一起看的。

（the teachers are doing what they can ）to teach students

to do 表示目的，来干嘛干嘛。what they can 整个充当do的宾语，而what又充当do的宾语