Ⅰ动词不定式：

  动词不定式的时态和语态

  1)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)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。

  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)不定式的完成体：

  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]不定式的完成进行体与不定式的完成体略有不同，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。