第3个回答 2014-04-16
动词不定式(to do)是初中英语课本中的一个重点。
动词不定式是由“to+动词原形”构成 (有时可以不带to)。其否定形式是“not+动词不定式”(not不与助动词连用)。它属于一种非谓语动词的形式,在句子中不能充当谓语,没有人称和数的变化,但它可以保留动词的性质,其本身可以带宾语或状语等附加成分(不定式和其附加成分称为不定式短语)。动词不定式(短语)的句法功能非常广泛,在句中可作主语、宾语、补足语、表语、定语及状语等成分。
一、作主语
(1)动词不定式作主语时,谓语动词常常用单数。例如:
To do morning exercises is useful for our health. 做早操有利于我们的健康。
To sweep the floor is my duty every day. 每天打扫地板是我的责任。
(2)如果动词不定式太长,常常用 it 作形式主语,而将真正的主语——动词不定式后置。例如:
It took me half an hour to walk there.我走到那儿花了半小时的时间。
It’s important for us to learn English well.对我们来说,学好英语是重要的。
二、作宾语
(1)能够接动词不定式作宾语的有 ask, agree, beg, decide, determine, fail, hope, manage, offer, plan, prepare, pretend, promise, refuse, wish 及 would like/love 等动词,但 finish, enjoy, miss, appreciate, mind, advise, suggest 等动词后面通常只能接动名词作宾语。例如:
I hope to visit this place again. 我希望能再度访问此地。
She enjoys reading very much.她非常喜欢读书。
The driver failed to see the other car in time. 司机没能及时看见另一辆车。
(2)动词不定式与名等词构成复合宾语时,通常要用 it 作形式宾语,而将真正的宾语——动词不定式后置。例如:
I think it our duty to obey the laws. 我认为遵守法律是我们的义务。
I found it difficult to see him here. 我发现在这里见到他是很难的。
三、作补足语
(1)某些动词在主动式中后接动词不定式作宾语补足语;在被动式中,由于原来的宾语变成了主语,故原来的宾语补足语变成了主语补足语。这类动词常用的有 consider, expect, tell, want, warn, wish,invite等。例如:
They told him not to be late again.他们告诉他不要再迟到了。→He was told not to be late again.
She invited me to have dinner with her yesterday.昨天她请我一起进餐。
(2)在feel(一感),listen to,hear(二听),let,make,have(三让),look at,see,watch,notice(四看)等词之后接不带to的不定式作宾语补足语,强调动作的完成过程;它们作被动句的谓语时,to要补上。如:
I heard her sing today.She sang wonderfully.今天我听见她唱歌了,她唱得非常精彩。
She was heard to sing today.今天有人听见她唱歌了。
She is often heard to sing this song(by us).我们经常听见她唱这首歌。
四、作状语
⑴动词不定式作状语可表示目的、原因及结果等,其逻辑主语就是句子的主语,因此动词不定式作状语往往用主动式。例如:
Come to see me again soon. 尽快再来看我。
I trembled to think of it. 我一想到那件事就不寒而栗。
You couldn't do that to save your life. 你即使为了救自己也不能那样做。
(2) only to do sth. 与 only doing sth. 都可作表示结果的状语,区别是:only to do sth. 表示一个与主语愿望相反的或出乎主语意料的结果, 或用来暗示最初的未能实现的动作;only doing sth. 表示谓语动词本身的动作造成的结果。例如:
I worked hard, only to fail at last. 我努力工作,结果最后却是失败。
He died, only leaving nothing but debts. 他死了,只留下一身债
五、作表语
(1)动词不定式往往放在系动词be(,become, sound, taste 等系动词后面一般不接不定式)的后面作表语,表示将来的情况,说明主语的内容。例如:
My wish is to become a teacher.我的愿望是当一名教师。
Your job today is to clean the playground. 你今天的工作是打扫操场。
(2)如果系动词后的动词说明主语的性质,特征,相当于形容词。这时就要用现在分词作表语,而不用不定式。例如:
He said that the story was interesting.他说这则故事很有趣。
六、作定语
(1)动词不定式常常放在名词或不定代词后面作后置定语,其逻辑主语往往是句子的主语,故动词不定式作定语时往往用主动式;如果动词不定式的逻辑主语不是句子的主语,该动词不定式要用被动式。例如:
Do you have anything to do tonight? 你今晚有什么事要做吗?
I am going to Shanghai tomorrow. Do you have anything to be taken there? 明天我要去上海。你有什么东西要捎去的吗?
(2)动词不定式作定语往往表示尚未发生的动作,如果动作已发生或正在发生,一般用现在分词作定语。例如:
I have no pen to write with.我没有钢笔写字。
The man standing there is Li Ming. 站在那里的那个人是李明。
七、和疑问词连用:
不定式前可用what,who,which,where,when,how,why等疑问词构成不定式短语,这种短语在句子中可作主语、宾语和表语等成分。
(1)作主语。例如:
When to start has not been decided. 什么时候出发还没定下来。
(2)作表语。例如:
The question is how to do the job well. 问题是怎样做好这项工作。
(3)作宾语。例如:
He told me where to find the book. 他告诉我了在哪找到这本书的。
Do you know how to play football? 你知道怎样踢足球吗?
祝你学习进步,
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