专门替中国人写的英语语法9-3：不定词（Infinitives）

　　9-3 不定词(Infinitives)

　　不定词=to+动词的原式。例如to go, to love, to eat等等，都是不定词，不定词和动名词的用法相似，以下全是用不定词用作名词的例子：

　　To love is to forgive.

　　To forgive your enemies will make you happy.

　　I like to eat chicken.

　　I asked my brother to come here.

　　He continued to read.

　　也许读者发现了不定词和动名词不同的地方：不定词不能用在介系词的后面，以下的句子都是错的：

　　*I am interested in to play piano.

　　*He is worried about to go abroad.

　　*I am in charge of to prepare for the party.

　　如何将不定词用成名词呢?

　　1.不定词可以用作主词：如

　　To play tennis is great fun.

　　To play safe in the stock market is necessary.

　　To be kind to others is important for every one.

　　To respect your parents shows good character.

　　2.不家词可以用成很多动词的受词：

　　I like to swim.

　　He loves to listen to jokes.

　　My brother seems to be different.

　　I agree to lend him money.

　　Do you like to sing?

　　3.不定词可以跟在代名词的后面，形式如下：

　　动词(verb)+代名词(pronoun)+不定词(infinitive)

　　例如：

　　I told him to work hard.

　　I asked my brother to come back home.

　　He expects his friends to help him.

　　My teacher told me to wait for him.

　　I invited my sister to go to see a movie.

　　4.不定词常用在上述句子的被动语气中，例如：

　　He was told to work hard.

　　My brother was asked to come back home.

　　His friend is expected to help me.

　　I was told by my teacher to wait.

　　My sister was invited to go to see a movie.

　　以下是更多的不定词例子：

　　To give is more meaningful than to receive.

　　I love to swim in cold weather.

　　He agreed to listen to my story.

　　He decided to go anyway.

　　I told him to buy my book.

　　I invited him to come to my house.

　　I asked him to cook for me tonight.

　　Students are asked to work hard.

　　He needs to work hard.

　　I want you to send this letter to my father.

　　He requires every student to read one novel every week.

　　Every student is required to read one novel every week.

　　读者一定会问，是不是动名词可以和不定词互调，答案是否定的，有些动词后面可以跟动名词和不定词，但也有些动词，后面只能跟动名词，有些动词后面只能跟不定词。

　　有些动词后面可以跟动名词或不定词：love, like, hate, start, begin,以下的动词，后面只能跟动名词：

　　Enjoy I enjoy eating good food.

　　Appreciate I appreciate your being kind to others.

　　Avoid You should avoid making mistakes.

　　keep on Keep on working hard.

　　keep Keep singing.

　　consider He considered leaving home.

　　finish He finished writing this book.

　　suggest May I suggest drinking a cup of coffee?

　　discuss We discussed traveling to New Zealand.

　　以下的动词正好相反，只能跟不定词

　　agree I agree to sign this letter.

　　plan He plans to go away.

　　want They want to rent a car.

　　decide He decided to work hard.

　　seem He seems to be very happy.

　　appear He appears to be very sad.

　　一个字非常特殊，必须讨论一下，那就是stop：

　　stop smoking 指不再抽烟了

　　stop to smoke 指停下来，开始抽烟