句型1：it+be+adj.(for sb./of sb.)to do

　　it is difficult(for me)to learn russian.(我)学俄语是件困难的事。

　　it is very kind of you to help me.你帮助我真是太好了。

　　句型2：it +be +adj.+that

　　it is true that he went there.他去了那儿，是真的。

　　句型3：it +be +time +for +n.

　　it +be +time(for sb.)+to do

　　it's time for class.该上课了。

　　it's time(for us)to go to school.(我们)该上学了。

　　句型4：it+be+时间/季节/天气/距离

　　it's seven now.现在七点了。

　　it's winter now.现在是冬季。

　　it's sunny today.今天阳光灿烂。

　　it's twenty miles to london.这里离伦敦有20英里。

　　句型5：it's one's turn(to do)

　　it's your turn to speak.轮到你发言了。

　　句型6：it +takes/took+sb.+some time +to do

　　it took me two hours to finish the work.我用了两小时完成这项工作。

　　句型7：it seems that...

　　it seems that he has been ill for a long time.他好像病了很长时间。

　　句型8：it +costs +sb.+some money +to do

　　it cost me 1，000 yuan to buy that bike.买那辆自行车我用了1000元。

　　句型9：it +be +some time +since...

　　it is three years since he came here.他自来这儿以来，已经三年了。

　　句型10：it +be +quite +a(an)+adj.+n.

　　it's quite a nice book.它是一本相当好的书。