动词不定式是由“不定式符号to+动词原形”构成的一种
非谓语动词结构。有些动词不定式不带to,动词不定式可以作句子的主语、
表语、宾语、定语、补语、状语或单独使用。不定式保留动词的某些特性,可以有自己的宾语、状语等。动词不定式和它后面的宾语、状语等一起构成短语,叫作不定式短语。
一、用作主语
直接把动词不定式置于句首的情况不多,多数情况用it作
形式主语,把真正的主语——动词不定式置于句末,特别是不定式短语较长时。动词不定式作主语,谓语动词用第三人称单数形式。带疑问词的不定式短语作主语常置于句首,复合不定式结构作主语常置于句末。如:
无论是形式主语,还是形式宾语,都要用it,不能用其他词。切记!
1.As young adults, it is our duty to try our best to deal with each
challenge... (p.8)
it是形式主语,真正的主语是文中的划线部分。
2.The head teacher said it was necessary to talk with his mother.
(p.16)
3.How to make requests politely is important.(p.93)
划线部分看成三单形式。
二、用作表语
动词不定式作表语,常说明主语的内容、性质、特征。如:
为什么大家写不出长句子?没有大量的积累。多背诵,多思考。
1.The best way to improve your English is to join an English club.
(p.7)
2.The first thing is to greet the teacher. (p.96)
三、用作宾语
1.可以接带to的动词不定式作宾语的动词主要有:
要求选择同意(ask, choose, agree),
期望决定学习(expect, hope, decide, learn),
宁可假装知道(prefer, pretend, know),
希望想要愿意(wish, want, would like / love)。
如:
1)We decided to talk to some students about why they go there. (p.88)
2)He prefers to eat white bread and rice.(p.50)
3)Id love to visit Mexico.(p.53)
2.动词decide, know, learn, show, teach,
tell...,介词结构on...可用疑问词带to的不定式短语作宾语,但why后面的不定式不带to。如:
1)Could you please tell me where to park my car?(p.92)
2)It gives advice on what to do in lots of different situations. (p.32)
3.动词feel, find, make, think等后面,可以用it作形式宾语代替真正的宾语——动词不定式,句子结构是...feel / find
/ make / ... it+adj. / n.+to do...。如:
这个知识点是重点,大家要记住。这样的句子在作文中是提分点。写出复杂的语法,让阅卷人眼前一亮。加分!!!
I find it difficult to remember everything. (p.98)
4.既可接动词不定式又可接v-ing形式作宾语,意思差别不太大的动词有begin, start, like,
love等。一般说来,动词不定式表一次、数次的具体动作、将来动作或动作的全过程,v-ing形式表习惯性的连续动作。如:
1)Then I started to watch English-language TV.(p.6)
2)I’m beginning to understand my Chinese roots, and who I am. (p.116)
begin用了进行时态,后面只接不定式作宾语,表示事情刚开始,还要继续下去。
3)I like to eat vegetables. (p.118)
感知动词like, love, know等一般不用进行时态。
5.后接动词不定式或v-ing形式作宾语,意思差别较大的动词有forget,
remember等。后接不定式作宾语,表动作尚未发生;后接v-ing形式作宾语,表动作已经发生。stop to do停下来做另外一件事,to
do是目的状语;stop doing停止做、不做当前这件事,doing是宾语。try to do尽力做,try doing试试看;go on to
do接着做另外的事,go on doing继续做原来的事。如:
1)When I left home, I had forgotten to bring it with me.(p.107)
2)I stopped using them last year. (p.121)
四、用作定语
1.句子的主语或宾语是动词不定式的逻辑主语,不定式与其所修饰的名词、代词等存在逻辑的动宾关系时,用动词不定式的主动式。如:
1)I have so many chores to do today.(p.112)
2)I cant think of any good advice to give her. (p.31)
3)Basketball has also become a more popular sport for people to
watch.(p.75)
也就是说,动词不定式可以做定语。
2.动词不定式所修饰的名词是place, time, way等时,
如:1)He needs time to do homework.(p.19)
2)Is that a good place to hang out?(p.88)
3)You want to know the best way to get around the city.(p.127)
3.在“
there be...”句型里,句子的主语是动词不定式动作的对象,常用主动式。如:
1)There’s just so much to see and do here.(p.49)
2)... but there are still many things to do there.(p.54)
五、用作补语
动词不定式作补语时,在主动语态句里补宾语,在被动语态句里补主语,句子的宾语或主语是不定式动作的逻辑执行者。