解析雅思阅读中的动词不定式

　　1)雅思阅读动词不定式的构成：(以动词“do”为例)

　　主动态：一般式"to do";完成式"to have done";进行式"to be doing";完成进行式“to have been doing”

　　被动态：一般式"to be done";完成式“ to have been done"

　　否定式：not+不定式

　　2)雅思阅读不定式的时态：

　　①不定式的一般式表示的动作与主句谓语动词表示的动作同时发生或之后发生。

　　He seems to know her address.(：=It seems that he knows her address.)

　　I hope to see you again.(=I hope that I’11 see you again.)

　　②不定式的进行体表示的动作正在进行，与主句谓语动词表示的动作同时发生。其用法主要有以下几种情况：

　　a 常用在"appear，happen，pretend，seem，hope，promise"之后。

　　She pretended to be listening attentively.

　　Tom appeared to be living in this area.

　　I hope to be earning my living in a year’s time.(I hope 1 will/would be earning my living)

　　I promised to be waiting at the door when he came out.

　　b 常用在"believe，consider，suppose，think，know，report，say，understand"等动词的被动式之后。

　　He is thought/known/believed/said/supposed to be living in this area = People think/know/ believe/ say/suppose that she is living abroad.[据认为(据知，据信，据说，据猜测)她住在国外。]

　　[注]“be supposed to”通常含有“应该”意思，表示一定的责任和义务，在雅思阅读中出现的很多。

　　You are supposed to know how to use a computer=You should know how to use a computer.

　　You are supposed to have been studying=You should have been studying.

　　Students are not supposed to cook in their dormitory=Students shouldn’t cook in their dormitory.

　　3)雅思阅读不定式的表达主题：

　　①用于表达发生在主句谓语动词之前的动作或状态，也可以表达预计在将来某一时刻之前完成的动作或状态。

　　I am sorry to have given you so much trouble.(=I am sorry that I have given you so much trouble.)

　　We’re leaving at five o’clock in the morning，and hope to have done most of the journey by lunchtime.

　　②不定式完成进行体主要用于“appear，seem，happen，pretend"等之后，也可用于"believe，know，report，say，understand"等动词的被动式之后。

　　He appears to have been waiting for a long time.

　　He is believed to have been waiting for a message.

　　[注]不定式的完成进行式与不定式的完成式略有不同，试比较：

　　He seems to have eaten the apples.(苹果已被吃光。)

　　He seems to have been eating the apples.(苹果尚未完全吃光。)

　　③不定式的完成体还可以表达本该发生却未发生的事情常带这种不定式的谓语动词有：“pretend，intend， appear，seem，should like，expect"等。

　　I meant to have telephoned you，but I forgot.

　　4)雅思阅读不定式的语态：

　　①在不定式之前能找到不定式所表达的动作的执行者时，此不定式用主动态;反之则用被动态。被动态在雅思阅读中出现的时候都是比较难以理解的时候。试比较：

　　We found the article hard to understand.(“understand”的执行者是“we”.)

　　He is reading the article to be published tomorrow.(“punish"之前没有执行者。)

　　②有时动作执行者(for sb.)不出现，也要用主动态。It is easy to do.(“It”既是主语，又是“do”的宾语，“to do”前省略了“for sb.”)

　　类似的还有：It is impossible to get there.

　　③在"there be"结构中，不定式既可以用主动态，又可以用被动态。

　　There is no time to lose/to be lost.(时间紧迫不能耽误了。前后意义无差别。)

　　There b nothing to do/to be done.(没事可干/无能为力。前后意义有差别。)

　　④习惯上用“to let(出租)”，“to blame(责怪)”的主动形式表示被动意义。

　　Nobody was to blame for the accident.(这场事故不能怪任何人。)

　　Tom asked her if she had any rooms to let.(汤姆问她是否有房要出租。)

　　在雅思阅读中，动词不定式的出现一般都会伴随着考题，所以大家可以在平时的练习中就予以关注，只有在平时的时候熟悉了，才能在雅思阅读考试的时候顺利的理解。