<例句>
It is careless of you to lose so much money.
你太粗心，掉了那么多钱。
<语法分析>
of...to do sth.用在句中作主语，可接形容词作表语。it作形式主语。而for...to do sth.除了在句子中作主语外，还可以作表语、宾语、定语和状语等，作主语时，其表语可以使形容词，也可以是名词。有些形容词，如nice,right,wrong,good和wise等都可用于这两个结构中，但是意思有所差异。
<触类旁通>
(1)It's very kind of you to help me .
你帮助我真是太好了。
语法分析：of...to do sth.结构用在句中作主语。
(2)My suggestion is for you to do your homework.
我建议你去做家庭作业。
语法分析：for...to do sth.结构在句子中作表语。
(3)I'd like for you to come here.
我想还是你来这里好。
语法分析：for...to do sth.结构在句子中作宾语。
(4)He has a lot of work for you to do.
他有很多活要你来做。
语法分析：for...to do sth.结构在句子中作定语。
(5)He opened the door for the students to come in.
他开门让学生进来。
语法分析：for...to do sth.结构在句子中作状语。
(6)It is important for your teachers to attend today's meeting.
参加今天的会议对你的老师很重要。
语法分析：在for...to do sth.结构中，不定式的逻辑主语可以是人或物，也可以是引导词there。
(7)You are kind to lead the blind man across the road.
你真是好心人，把盲人引过马路。
语法分析：for...to do sth.结构中，后面的名词或代词与前面的形容词有逻辑上的主表关系。
<巩固练习>
(1)It is impossible for you _____ [get] there in such a short time.
(2)It will be a mistake for me not _____[help] them.
(3)It is possible for us to spend three hours _____[complete]the composition.
(4)It will take three hours for us _____[complete]the composition.
(5)It is a good idea for the present _____[give] to her.
(6)It is a pity for there _____ any disagreement in the company.
(7)It is wrong of the hunter _____[kill] the monkey.
<参考答案>
(1)to get (2)to help (3) completing (4)to complete (5)to be given (6)to be (7)to kill
