请解析“It's nice of you to say so."说出其含义,表达语境等.

请解析“It's nice of you to say so."说出其含义,表达语境等. It's very nice of you to say so. It's nice of you to say It's very nice ------ you ------ so.A.of,to say B.for,to say It's really nice of you to say so.中文意思?为什么用of不用for? It is ____ nice of you to say so. It's very handsome of you to say so. It's very kind of you to say so it's kind of you to say so It is (really) nice of you to say so.为什么括号内要填really? 1.It is ___ nice of you to say so . A. truly B. really 2.At It is _____ nice of you to say so.咋填