A: Do you know Jim?
B: Yes. We were classmates three years ago.
A: What do you think of him?
B: He has always been good at fishing in troubled waters.
fish in troubled waters
Fish in troubled waters是俚語，相當于“take advantage of a Bad situation to loot”或者是“to involve oneself in a difficult, confused, or dangerous situation, especially with a view to gaining an advantage”，可譯為：趁火打劫，乘人之危，混會摸魚等。
e.g. They were clearly seeking to fish in troubled waters.
e.g. Frank is fishing in troubled waters by buying more shares of that company.
e.g. They are supposed to be in financial difficulties. The company could make more money by selling armaments abroad, but they would be fishing in troubled waters.
1. be good at：擅長于……
e.g. He is good at managing money matters.
e.g. He' s well-intentioned but not very good at getting things done.
e.g. He is good at initiating projects but rarely follows through with anything.
e.g. The teacher is good at firing up the imagination of his pupils.
2. think of：看待……，認為……
e.g. What do you think of the terms of payment?
e.g. Susan and her fiance think of their letters as cords of love.
e.g. She did not sufficiently think of making herself a nest for him.
e.g. She doesn't care a straw what men think of her.