if条件句的用法有哪些

发布网友 发布时间：2024-05-12 15:23

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热心网友 时间：2024-06-01 02:55

对将来进行假设主要有三种情况：

1,if条件从句是谓语用动词过去式,则后面的主句是情态动词加动词原形

例：If I came tomorrow ,we would have the meeting.

2,if条件从句是were to形式,则后面的主句也是情态动词加动词原形

例：If it were to rain tomorrow ,the meting would be put off.

3,if条件从句是should do形式,则后面的主句可以用情态动词加动词原形,也可以用祈使句（但注意,祈使句仅适用于前面从句是should do形式的）

例：If it should rain tomorrow,don't expect me./I would not go there.

扩展资料

对现在事实相反的虚拟语气

1、表示与现在事实相反的情况

从句：If+主语+动词一般过去时(Be动词用were)

主句：主语+ should/would/might/could+do：

If I were you，I would take an umbrella.

如果我是你，我会带把伞。（事实：我不可能是你）

If I knew his telephone number，I would tell you.

如果我知道他的电话号码，我就会告诉你。（事实：不知道）

If there were no air or water，there would be no living things on the earth.

如果没有水和空气，地球上就不会有生物。(事实：地球上既有空气也有水)

If I had any money with me，I could lend you some.

如果我带钱了，我就会借给你些。（事实：没有带钱）

If he studied harder，he might pass the exam.

如果他再努力些，就能通过考试了。（事实：没有努力）

If I were you， I'd wear a shirt and tie.

如果我是你，我就会穿衬衫和领带。(事实：我并不是你）

2、表示与过去事实相反的情况

从句：If+主语+had+done

主句：主语+should/would/might/could+have done

eg：If I had got there earlier，I should/would have met her.

如果我早到那儿，我就会见到她。（事实：去晚了）

If he had taken my advice，he would not have made such a mistake.

如果他听我的劝告的话，就不会犯这样的错误了。（事实：没有听我的话）

参考资料：百度百科-虚拟语气