it was friendly __him __ offer his help of to 为什么要用of而不是for呢

It's quite n_____ for a person to refuse the offer of help f it's __ nice of you to help him.填truly还是really,为什么? It is very nice of you to help me 为什么要用of It's friendly of you to help me with my English.（改同义句） It was very good __ him to help us A by B of C from D about it was nothing.happy to be of help. 为什么“It's helpful of you to help me clean the classroom”为什么要用 It is very kind of you to help me的help前为什么要加to It is wrong of you to ignore their avice.中为什么要用of,不用for? it"s the best __(of/for) them all.为什么? it's very nice for/of/to you to help me of/with/for my Engli It's very kind of you to help me 为什么用of