see through (someone or something)
Definition: to understand someone’s real intentions, even though they are trying to hide them.
(This phrasal verb has more than one meaning.)
E.g.1: He told them that he was trying to help them, but they could see through him. They knew that he was really trying to help himself.
E.g.2: She saw through what they were doing and refused to give them her support.
This phrasal verb cannot be separated.