Unit 1 Helping those in need 语法Grammar 动词不定式-2023-2024学年八年级英语下册单元语法精讲精练（沪教牛津版）

Unit 1 Helping those in need 重点语法 动词不定式 （时间：40分钟，满分：100分） 【概念】 由“to+动词原形”构成，在句子不能作谓语，没有人称和数的变化。其否定形式为：not to+动词原形。其被动语态形式为：to be+动词过去分词。动词不定式在句中可以作主语、宾语、表语、定语、状语和补语。 1. 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 2. 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. / 3. 动词不定式作目的状语 (1) 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. In order to protect pandas, the government is setting up nature parks. (2) 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： 1) I feel very lucky to have him. 2) 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： 1) I’m too tired to do it well. 2)The room is big enough for three people to live in. 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: (1).把不定式置于句首。如: To learn English well is very important. (2).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： 1.The best way is to join an English club. 2.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. 1)I have so many clothes to wash today. 2)I can’t think of any good advice to give her. 感官动词如see, hear, watch, notice, observe等以及使役动词make, have, let 等在跟不定式作宾语补足语时要省略不定式符号to，但在转换成被动语态时必须加上to。 Lucy asked him to turn down the radio.露茜叫他把录音机音量关得小一些。 I consider him （to be） a great man.我认为他很伟大。 She was considered （to be） too