英语语法知识点详解 零条件句.docx

英语语法知识点详解 零条件句In English, there are four types of conditional sentences:英语中有四大类型条件句：0 – The Zero Conditional 零条件句1 – The First Conditional 第一类条件句2 – The Second Conditional 第二类条件句3 – The Third Conditional 第三类条件句Each conditional sentence has an IF clause, and a main clause. And all the four types of conditionals use the conjunction IF.条件句由两个组成部分：IF从句 + 主句四大类型条件句均使用连词IFIF clauseIF从句Main clause主句0IF + present simple,IF + 一般现在时,present simple一般现在时to talk about permanent truths, such as scientific facts, and general habits谈论客观真理，如科学事实，和一般的习惯★ If you heat water, it evaporates.★ 如果你加热水，水就会蒸发。

1stIF + present simple,IF + 一般现在时,will + infinitivewill + 动词不定式to talk about possible and likely future outcomes谈论将来可能发生的情况★ If you study hard, you will pass the exam.★ 如果你努力学习，你将通过考试2ndIF + past simple,IF + 一般过去时,would + infinitivewould +动词不定式to talk about improbable or impossible situations in the present or future谈论现在或将来不可能发生的情况与现在事实相反（非真实条件句）★ If I won the lottery, I would buy a big house.★ 如果我中彩票了，我会买一栋大房子3rdIF + past perfect,IF + 过去完成时,would have + past participlewould have + 过去分词to describe an event for the past that did not happen描述过去未发生的事情与过去事实相反（非真实条件句）★ If I had studied harder, I would have passed the exam.★ 如果我当时更努力地学习，我早就通过考试了。

The IF clause gives us the condition or situation, and the main clause gives us the result. The Zero and the First Conditional express real or possible conditions and results. The Second and the Third Conditional express impossible, hypothetical, unreal conditions and results.IF从句提供条件或情况，主句描述产生的结果零条件句和第一类条件句描述真实或可能发生的条件和结果第二类条件句和第三类条件句描述不可能发生的、假设的、不真实的条件和结果With all conditional sentences, the order of these clauses is not fixed. So, you can swap them around. And even when you change the order of the clauses, the meaning is the same. In writing, if your IF clause comes first, add that comma. If your main clause comes first, you don’t need a comma.在所有类型的条件句中，IF从句和主句的顺序可以互换。

即使句子的顺序发生改变，其含义也不会发生变化在书写中，如果把IF从句放在句首，中间加个逗号，再加主句如果主句放在句首，则无需加句号If I practice, I will get better.I will get better if I practice.The Zero Conditional 零条件句◆ A Zero Conditional sentence consists of two present simple verbs. Both parts of the sentence are in the present tense.零条件句的IF从句和主句均由一般现在时的动词引导If this thing happens, that thing happens.IF + 一般现在时， 一般现在时◆ We use the Zero Conditional to talk about permanent truths, such as scientific facts, and general habits.谈论客观真理，如科学事实，和一般的习惯★ If you heat water, it evaporates.如果你加热水，水就会蒸发。

★ If you leave ice cream in the sun, it melts.如果你把冰激凌放在太阳下，它就会融化★ People die, if they don’t drink enough water.如果人们不喝足够多的水，就会死亡★ If you put a stone in water, it sinks.如果你把石头放在水里，它就会沉下去★ If you eat a lot, you put on weight.如果你吃得多，你就会发胖You can usually replace IF with WHEN OR WHENVER, without the meaning changing.这里的IF可以用WHEN OR WHENVER替代，而不会改变其意义◆ We often use the Zero Conditional to give instructions, with the imperative in the main clause."零条件句 "可以用来发出指令，主句使用祈使句★ Text me if you get lost.如果你迷路了，就给我发短信。

★ If you accidently drop some trash, pick it up.如果你不小心掉了一些垃圾，就把它捡起来★ If Mary calls, don’t answer the phone.如果玛丽打来，不要接。