▲描述人的性质、特征等品质类形容词，可以直接作“人”的表语：Sb. is + 形容词。这类形容词有：kind, nice, good, polite, impolite, rude, patient, careful, careless, wise, clever, selfish, unselfish, foolish, silly, stupid, cruel, brave, crazy等。例如：

You are very kind.

He was very patient.

▲也可以指某人做了某事所体现的这种品质。这时，可以用代词that或it充当其主语，然后加of sb. 例如：

It is very kind of you. （对你做的事表示谢意）

That was stupid of me. （做那事我太愚蠢了）

▲此外，这类形容词还用在“It is/was+ adj.+of sb.to do sth.” 结构中，不定式前的形容词描述的是不定式逻辑主语的性质、特征、品质，由of引出不定式的逻辑主语，注意不用for sb.。这时，逻辑主语与前面的形容词存在主表关系（看括号里的句子）。

    It is kind of you to help us.(=You are kind to help us.)你帮助我们真是太好了。

    It was silly of you to trust such a man.(=You were silly to trust such a man.)

    你太愚蠢了，竟然相信这样一个人。

    It is selfish of him not to do anything for the orphans.(=He is selfish not to do anything for the orphans.)他很自私不愿为孤儿们做点事。

    It's unfair of you to say such things about her.(=You are unfair to say such things about her.)你这样说她太不公平了。