It’s kind of you to say so这个句子怎么翻译,为什么有个of 和 to 后面的so是所以的意思为

It's very kind of you to say so it's kind of you to say so It's so kind of you和you are so kind是一样的意思吗? It's very kind of you to say so.什么意思 It's really nice of you to say so.中文意思?为什么用of不用for? It's very kind ( )you to say so.A.to B.of C.for -__ hard work you have done!-It's very kind of you to say so ____hard work you have done It's very kind of you to say so. 英语翻译RT请翻译出：愿意 这个词呀 我想要的翻译是it's so kind of you to willing to It's very nice of you to say so. It's very handsome of you to say so. It's very nice ------ you ------ so.A.of,to say B.for,to say