if虚拟语气的用法归纳
IF虚拟语气是英语中的一种重要语法现象，主要用于表示与现实相反的假设、愿望、建议等。它分为两种形式：if条件句和if非条件句。以下是对IF虚拟语气用法的详细介绍：
一、if条件句
1. 表示与现在事实相反的假设：
If + 主语 + 过去时态，主语 + would/could/might/should + 动词原形。
例如：If I were you, I would go to the party.（如果我处在你的位置，我会去参加派对。）
2. 表示与过去事实相反的假设：
If + 主语 + had done，主语 + would/could/might/should + have done。
例如：If he had come to the meeting, he would have known the plan.（如果他参加了会议，他就会知道这个计划。）
二、if非条件句
1. 表示建议、劝告：
主语 + should/would/might/ought to + 动词原形。
例如：You should go to the party.（你应该去参加派对。）
2. 表示愿望：
主语 + could/would/might + 动词原形。
例如：I wish I were a bird.（我希望我是一只鸟。）
3. 表示假设：
If + 主语 + 动词过去式，主语 + would/could/might + 动词原形。
例如：If I had time, I would go to the park.（如果我有时间，我会去公园。）
三、if虚拟语气的特殊结构
1. 省略if，将were、had、should等词置于主语之前：
主语 + were/had/should + 动词原形。
例如：She were here, she would meet him.（如果她在这里，她会见到他。）
if的虚拟语气的用法例句
一、if的虚拟语气简介
虚拟语气是英语中一种特殊的语法现象，常用于表示假设情况、与实际情况相反的条件或无法实现的愿望等。if引导的条件句中，根据其所表示的条件类型和时间性质，使用不同形式的虚拟语气。
二、与现在事实相反的虚拟语气
1. 假设条件：如果+动词过去式（be动词用were）
例句：If I were a bird, I would fly high in the sky.
2. 假设条件：如果+动词过去完成时（had + 过去分词）
例句：If he had studied harder, he would have passed the exam.
三、与现在事实相反但可能实现的虚拟语气
1. 假设条件：如果+动词过去式（be动词用were）
结果：主将从现
例句：If it rained tomorrow, I would stay at home.
2. 假设条件：如果+动词过去完成时（had + 过去分词）
结果：主将从现完成
例句：If he had invited me, I would have gone to the party.
四、与过去事实相反的虚拟语气
1. 假设条件：如果+主语+had + 动词过去分词 结果：主语+would/could/might + have + 过去分词
例句：If I had known the truth, I would have made a different decision.
2. 假设条件：如果+主语+had not +过去分词形式，结果也用一般过去时态
例句：If we hadn't missed the train, we would have arrived on time.
五、与将来事实相反的虚拟语气
1. 假设条件：如果+动词过去式（be动词用were）
If引导的虚拟语气
与现在事实相反的假设
If+主语+动词过去式（be动词用were）
主语+should/would/could/might+动词原形
例句：If I had time, I would attend the meeting.
If I were you, I should seize the chance to go abroad.
与过去事实相反的假设
If+主语+had+过去分词
主语+ should/would/could/might +have+过去分词
例句：If you had came yesterday, we would have had the meeting.
与将来事实相反的假设
If+主语+动词的过去式
If+主语+were to +动词原形
If+主语+should+动词原形
例句：If you came tomorrow, we would have the meeting .
If it were to rain tomorrow, the sports meeting would be put off.
If he should not come tomorrow, we should put off the meeting till next Monday.
错综时间条件句即混合条件句：主句与从句的动作发生在不同的时间，主句与从句的谓语动词的虚拟语气形式因时间的不同而不同。
If you had asked him yesterday, you would know what to do now.
如果你昨天问过他，今天就知道做什么了。
虚拟条件句的从句部分含有were should had 时，可以省略if,把were should had 移到从句的句首，实行倒装。例如：Were they here now, they could help us.=If they were here now,
If 条件句 虚拟语气
if 条件句
从句 主句
现在 动词过去式或were Would /should/ could/ might +do
将来 动词should 或were to do Would /should/ could/ might +do
过去 动词had done Would /should/ could/ might +have done
省略if 从句倒装 不变
If I were you ,I wouldn’t do that
If it hadn’t rained ,I would have been out to play
If I were to be a doctor,I would help those patients
Hadn’t it rained, ,I would have been out to play
情态动词完成式暗示虚拟语气：
Should have done 本该做。。却没做
Shouldn’t have dong 不该做。。却做了
Needn’t have done 没必要做 。。。却做了 。。。
例如：I should have called me .
强化训练：虚拟语气
1．Were it not for the snowy weather, we ----- all right.
A. would be B. would have been C. were D. may be
2.-------- more careful, his ship would not have sunk.
A. If the captain were B. Had the captain been
C. Should the captain be D. If the captain would have been
3. If he ------me tomorrow, I would let him know.
