不定式做主语二

It's+ 形容词 +for/of 逻辑主语 + 不定式短语

It's kind of you to think so much of us.难为你这样替我们着想。

It's very nice of you to be so considerate.你太好了想得这么周到。

It's unwise of them to turn down the proposal.他们拒绝采纳这个建议是不明智的。

It's bad for your health to sit up to late at night.晚上睡得太晚对你的健康有害。

It's not easy for you to get him to change his mind.你要说服他改变主意是不容易的。

It's impossible for him to give up smoking.要他戒烟是不可能的。

适合这个结构的形容词有以下这些：

一、倾向用"of"

Kind, good, nice, wise, unwise, clever, silly, wrong, right, foolish, stupid,

Careless, considerate, rude, naughty, impolite

二、倾向用"for"

Costly, illegal, immoral, unfair, unhealthy, unjust, unlawful, unreasonable,