盖瓦领条间距是多少

If 条件句小结

在英语学习中，同学们总是在if条件句的使用上出现问题，现将if条件句的基本规律总结如下：
1）零条件句：谈论总是发生，一般存在的现象时使用。
句子结构：从句If+一般现在时，主句用一般现在时If + Simple Present,+ Simple Present
OR
Simple Present+ If + Simple Present
Examples：If you boil an egg, it becomes solid.
If you heat something, it becomes hotter.
I always listen to music if I jog.
在零条件句中，我们可以用when代替if

2）第一条件句：用于描述将来很可能发生的事件
句子结构：从句if+一般现在时，主句将来时（主将从现）If + Simple Present,+ Will
OR
Will+ If + Simple Present
Examples：Lisa will be very happy if she wins the prize.
If it rains, then we will stay at home.
If I see Sam, I will ask him to give you a call.
第一条件句中，主句可以用shall, can, may等情态动词代替will

3）第二条件句：用来描述将来不太可能发生的事情，或者和现在事实相反的事件
句子结构：条件句if+一般过去时，主句would+动词原形If + Simple Past,+ Would + Base Form
OR
Would + Base Form+ If + Simple Past
Examples：If I won a million dollars, I would travel around the world.
She would quit schoolif her parents agreed.
I would be surprised if I saw pigs in the sky.
OR
You would see John if you were here now.
If things were different, we would be happy.
We would be good friendsif she were nicer.
第二条件句中，我们可以用could, should, might代替will注：第二条件句中只能用were，不用was4）

4）第三条件句: 用于描述和过去事实相反的事件
句子结构：从句if+过去完成时，主句would have + 过去分词If + Past Perfect,+ Would have + V3
OR
Would have + V3+ If + Past Perfect
Examples：If I had woken up on time, I would have taken the bus.
If I had told Sarah the truth,I would have felt much better.
If it hadn't rained yesterday,we would have enjoyed a nice picnic.
第三条件句中可以用should have, could have, might have代替would have