3、有時(shí)，不定式跟作主語(yǔ)時(shí)一樣，可由it來(lái)代替，而把不定式放到后面去He makes it a rule to take a walk before breakfast.

　　I think it interesting to play football while it is snowing hard.

　　We find it difficult to get everything ready before the time you require.

　　She cosiders it important to make friends with them.

　　I don't think it necessary to argue with them on this problem.

　　4、有時(shí)THERE和TO BE連用表示“有”或“存在(某情況)”等

　　It is impossible for there to be any more.

　　Would you like there to be a meeting to discuss the problem?

　　I expect there to be no argument about this?

　　有時(shí)在個(gè)別的介詞后可用“疑問(wèn)詞+不定式結(jié)構(gòu)”作其賓語(yǔ)

　　He has his own decision of how to do it.