肯定句变否定句研究报告.doc

肯定——否定 一、动词 be 的否定式 动词be根据不同的人称和时态可以有am, is, are, was, were等不同形式，可用作连系动词(表示“是”、“在”等)和助动词(用于构成进行时态和被动语态等)，但不管何种情况，构成否定式时，一律在其后加not。 I’m old, but you’re young. →I’m not old, but you’re not young. He was reading and I was writing. →He was not reading and I was not writing. 二、 动词 have 的否定式 动词have根据不同的人称和时态可以有have, has, had等形式，可以用作实意动词和助动词，分以下情况讨论。 用作实意动词表示状态，如表示拥有、患病或用于have to表示“必须”等，在构成否定式时可以直接在其后加not，也可根据情况在其前使用don’t, doesn’t， didn’t。 He has a car. →He hasn’t a car. / He doesn’t have a car. He had some dictionaries. →He hadn’t any dictionaries. / He didn’t have any dictionaries. You have to go with him. →You haven’t to go with him. / You don’t have to go with him. 【注】have to构成否定式时以在其前加don’t等较为常见。 用作实意动词表示动作，如表示“吃(=eat)”、“喝(=drink)”、“拿(=take)”、“收到(=receive)”、“度过(=spend)”等，构成否定式时不能直接在其后加not，而应根据情况在其前使用don’t, doesn’t, didn’t 。 He had some cake for breakfast. →He didn’t have any cake for breakfast. We had a good holiday. →We didn’t have a good holiday. 用作助动词构成完成时态，其否定式只能在其后加not。 I have read the book. →I have not read the book. He had left when I arrived. →He hadn’t left when I arrived. 三、情态动词的否定式 情态动词的否定式一般在其后加not构成。 I can finish the work in an hour. →I can’t finish the work in an hour. You must go with us. →You mustn’t go with us. We should help them. →We shouldn’t help them. 四、实意动词的否定式 一般实意动词的否定式，通常应根据不同时态和人称在实意动词之前加don’t, doesn’t, didn’t等。 He works in a bank. →He doesn’t work in a bank. We often hear from her. →We don’t often hear from her. I met her at the station. →I didn’t meet her at the station. 注意： 加上does not或did not改为否定句以后，要把原句的动词改为原形动词，特别是行为动词do的第三人称单数does和过去时did，在主语后面加上doesnt或didnt以后，千万要注意把句中的does或did改为 do。 五、祈使句的否定结构为：dont十原形动词 改为否定句时，要在句首加上dont，其它不变，即： Look out of the window． →Dont look out of the window． 当陈述句中含有something这个词时 把句子改为否定句有两种方法：其一，在句中相应位置加not，再把something改成anything；其二，直接把something改为nothing即可。 There is something wrong with the radio． 把这个句子改为否定句有两种方法： 其一，先把not加在is后面，再把something改为anything即：There is not an