学文网我们先来看一个笑话：
Wife: “There is nothing left in the refrigerator. Peter, Can you go shopping with me?”
Husband: “Sorry, I can’t.”
Wife: “Why?”
Husband: “Because I haven’t finished reading the newspaper yet.”
Wife: “Then we can go after you finish reading it.”
Husband: “But I’m not sure how long it will take.”
Wife: “You don’t want to go with me, do you?”
Husband: “No, I don’t.”
Wife: “Why?”
Husband: “The supermarket is too far.”
Wife: “No road is far with your wife.”
Husband: “Actually, not everyone likes shopping.”
Wife: “But you said you liked shopping with me before we got married.”
Husband: “Since the fish has got hooked (上钩), why do I need the bait (鱼饵)?”
Wife: “What did you say?”
Husband: “No, nothing.”
Wife: “Even marrying a devil is better than marrying you.”
Husband: “It’s impossible. It’s forbidden for close relatives to get married.”
想必大家已经明白丈夫最后一句话的意思了。这则笑话含有很多否定句。今天，我们就来看看英语中否定句的构成。
1. 助动词 + not
该否定结构最为常见，也是大家最为熟悉的。
例如：You mustn’t let someone take advantage of your generosity or you’ll end up in the poorhouse. 不要让别人认为你的慷慨是理所当然，否则你将终老于救济院。
I didn’t use (=used not) to like music, but now I’m getting interested. 我以前不喜欢音乐，但是现在我很感兴趣。
祈使句的否定只需在动词前加don’t即可。
2. 否定副词seldom, never, hardly, rarely, little, few, none, nowhere, neither在句中可构成否定句。
例如：Taking a breath is such a common thing that we rarely even notice we are doing it. 呼吸是一件再普通不过的事情，以至于我们几乎没有注意我们正在做。
3. 非谓语动词的否定
非谓语动词的否定直接在分词前加not即可（不定式的否定为not to + 动词）。
例如：It’s unnecessary to worry about the unknown things in the future. 没有必要为未来未知的事情担忧。
Not knowing the language, she failed to understand what they were talking about. 语言不通，她不知道他们在说些什么。
When my father passed away, I regretted not having spent more time with him. 爸爸去世后，我后悔没有多抽出时间陪他。
4. 部分否定
当all, both, every, everyone, every day, everything, everywhere, many, always, completely等词与not连用时，是对一部分的否定，意为“并非都是，不是每个都是”。
例如：Not all is gold that glitters. 发光的不都是金子。
I don’t agree with all of you. 我并不完全同意你们所有人。
5. 完全否定
no, never, none, nobody, nothing, nowhere, neither... nor...表示完全否定。
例如：The man who saved her life was nowhere to be found. 救她生命的那个男人到处都不见踪影。
You will never know how much your mother loves you. 你永远都不知道你的妈妈有多爱你。
6. 双重否定
否定词not可置于带有否定前缀的单词前，构成双重否定；“not/never... without...”也可表示双重否定。
例如：It’s not uncommon for people to dream about their favorite film stars. 人们梦到他们最喜欢的电影明星是件很寻常的事情。
We can’t live without air or water. 没有空气和水我们无法存活。
7. 否定转移
think，believe，expect，suppose等词引导否定意义的宾语从句时，其否定转移到主句。
例如：I don’t imagine that taxes will be reduced this year. 我认为今年不会降低税收。
8. 否定形式表示肯定意义的句型
（1） “can’t/couldn’t/never... too”表示“无论怎样也不过分”。
例如：A man can never have too many friends. 朋友越多越好。
（2） “can’t/couldn’t be... enough”表示“无论怎么都不够”。
例如：You can’t be careful enough when driving. 开车时越小心越好。
（3） “never too... to...”该句型是对“too... to...”的否定，实则表示肯定。
例如：It’s never too old to learn. 活到老，学到老。
其他我们学过的“not... until”“hardly... when”“no sooner... than...”“would rather... than...”也都是常见的否定结构。只要在学习过程中善于观察和总结，掌握这些语言结构并不是难事。