非谓语动词的一般式表示的动作与谓语动词表示的动作同时发生或在其后发生，非谓语动词的完成式表示的动作发生在谓语动词表示的动作之前。
1.动词不定式
例1：A lot of young people are learning to drive cars. (同时发生)
例2：All of us expected to discover a new oil field. (非谓语动词动作发生在后)
例3：He is said to have studied English for three years. (非谓语动词动作发生在前)
注：动词不定式的完成式有时用在intended， expected， meant， were to， was to等过去式的动词后面，表示未实现的行为。例如：
1)I meant to have sent the book to you by mail. (我本想把这本书邮寄给你的。)
2)He was to have been the new ambassador， but he fell ill. (他原是要任新大使的，但是他病了。)
2.动名词
例1：I am thinking of getting a new dictionary. (非谓语动词动作发生在后)
例2：We enjoy watching colour TV. (与谓语动词动作同时)
例3：He forgot having promised to write things for us. (非谓语动词动作发生在前。)
3.分词
例1：Singing a song， he came into the room. (非谓语动词动作与谓语动词动作同时发生)
例2：Having written his composition， he went to have a heart to heart talk with Wang. (非谓语动词动作发生在前)
非谓语动词的比较
1.动名词和动词不定式在用法上的比较
(1)一般说来动名词所表示的动作在意义上是比较抽象的、一般的，时间概念不强，不是指某一次的动作;而动词不定式所表示的动作则往往是具体的一次行为。例如：
1)I like swimming， but I don't like to swim today.
2) They prefer staying indoors when the weather is cold.
3) Would you prefer to stay at home this evening?
(2)动词不定式的逻辑主语，常常是句子的主语或句中的某个词;而动名词的逻辑主语可能是句子主语或句中某个词，也可能是泛指一般人物，在句子里是找不着的。例如：
1)I hate to be sitting idle. (我不想闲坐着。)(指自己)
2)I hate saying nothing at a meeting but gossiping afterwards. (我不喜欢开会不说会后乱说。)(可能指自己，也可能泛指一般人)
(3)有些词后既可接动名词亦可接动词不定式，但意义不同，如stop， remember， forget， neglect， omit， dislike， detests， begin， continue， start， regret， intend， attempt， propose等。例如：
When the teacher came in， the students stopped talking. (talking 是宾语，指停止讲话这个动作)
When the teacher came in， the students stopped to talk. (to talk是目的状语，指停下前一动作来进行talk)
Remember， forget doing something (指已做过的事)
Remember， forget to do something (指未做过的事)
2.动名词和现在分词在用法上的区别
(1)作定语的区别。分词往往表示它所修饰的词所做的动作，即逻辑主语是它所修饰的词;动名词往往表示与它所修饰的词有关的动作，即所修饰的词不能充当逻辑主语。例如：
the raging storm (= the storm that is raging) (狂暴的风雨)(分词)
scorching heat (= heat that is scorching) (炙人的热气)(分词)
sleeping car (= a car for sleeping) (动名词)
working method (= method of working)(动名词)
(2)作表语的区别。分词作表语时保持它的形容词特征，动名词作表语时保持它的名词特征。动名词作表语时常可与主语互换位置，分词则不行。例如：
The novel is interesting. ( 现在分词)
My job is teaching English. (动名词)
(3)作状语的区别。分词具有副词特征，可以直接用作状语;动名词不具有副词特征，不能单独作状语，只有与介词结合时才能作状语。例如：
1) Hearing the news， they immediately set off for the station. (分词作状语)
2) Given another chance， I'll do it much better. (分词作状语)
3) After finishing his homework， he went to the reading-room. (动名词与介词一起作状语)
4) On coming in she laid a file of documents upon the table. (动名词与介词一起作状语)
3.动词不定式作宾语补语和现在分词作宾语补语的区别
动词不定式只说明宾语的一个动作，而分词则说明宾语的动作正在进行。例如：
1)Just then he heard someone sing in the next room. (在那时，他听见有人在隔壁房间里唱歌。)
2)Just then he heard someone singing in the next room. (在那时，他听见有人正在隔壁房间里唱歌。)
（责任编辑:doublejp）
