They have done what they can to help her.
请问老师,宾语从句中,can后面还少了动词吗?
They have done what they can to help her. = They have done what they can (do) to help her.
what they can (do) to help her 是宾语从句, (do) 通常省略, to help her 是动词不定式短语作目的状语。