八年级英语动词不定式+双宾语讲解及练习.docx

一．动词不定式含义 专题三：动词不定式+双宾语 4. 动词不定式作主语 动词不定式作主语，句子的谓语动词常用单数，其位置有以下两种: 当我们要表示“想做某事、需要做某事或决定做某事”时，就会出现两个动词连用的情况， 这时应如何表达呢?同学们自然会想到 want to do sth.，need to do sth.和 decide to do sth.等表达方式。行为动词后的动词都采用了“to+动词原形”的结构。我们把这种结构称为动词不定式。动词不定式没有人称和数的变化，在句中不能作谓语。 二．动词不定式的功能 动词不定式作宾语 动词+to do sth.表示的多为将来的行为。 如：want to do sth. / hope to do sth. / learn to do sth. / try to do sth. / decide to do sth. / forget to do sth. / remember to do sth. / stop to do sth./ plan to do sth.等 to 有时可省略，结构为动词+do sth. had better do sth. / why not do sth. 动词不定式作宾语补足语 宾语补足语是对宾语的补充说明，结构：“动词+宾语+动词不定式”。其否定结构要在to do 前面加 not,构成 not to do。 如：allow sb. to do sth. / choose sb. to do sth. / want sb. to do sth. / tell sb. to do sth. / ask sb. to do sth. / invite sb. to do sth. / 在表示感觉、祈使等意义的动词 help, make, let, have, feel, see 等后接不带 to 的不定式。 动词不定式作目的状语 如果表示“做某事是为了什么”，可以用动词不定式表示目的，常与soas，in order 等构成短语不定式既可以放在句首，也可以放在句尾。如: He stopped to have rest.=To have rest, he stopped. She came to this city to visit her daughter. In order to protect pandas, the government is setting up nature parks. 根据表达的需要，动词不定式在句中还会有不同的语法功能，除了作目的状语外，还可以作原因状语和结果状语等。 ①原因状语，多见于“sb.+be+adj.+to do...”结构句中。如： I feel very lucky to have him. he ran out of money to buy old bikes. ②结果状语，多见于“too...to”，“enough to...”结构句中。如： I’m too tired to do it well. The room is big enough for three people to live in. 把不定式置于句首。如: To learn English well is very important. 用 it 作形式主语，把真正的主语置于句后，常用于下列句式中。 ①It+be+名词+to do It ‘s our duty to take good care of the old. ②It takes sb. some time to do sth. It took me two hours to go there. ③It+be+形容词+for(of)sb.+to do sth. It ‘s difficult for us to finish it in an hour. It ‘s kind of you to help me. 5. 动词不定式作表语 动词不定式作表语，常说明主语的内容、性质、特征。如： The best way is to join an English club. The first thing is to listen to the teacher carefully. 6. 动词不定式作定语 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. I have so many clothes to wash today. I can’t think of any good advice to give her. We have no houses to live in. Exercise: 用括号内单词的适当形式填空一、动词不定