疯豆：省略if的条件句
在书面语中，非真实条件句中有were, had, should时，可以省略if，而把were, had, should放在主语前，用倒装结构。
Were it necessary, I might go without delay.如果需要的话，我可以立即去。（= If it were necessary......）
Had you taken my advice, you wouldn't have failed in the exam.你要是听了我的建议，就不会考试不及格了。（= If you had taken my advice......）
Should I have time, I would call on her.要是有时间，我就去看她。（= If I should have time......）
D．错综条件句
虚拟条件句中的主句和从句涉及的动作发生的时间不一致，这时主句和从句的谓语形式应按照各自动作发生的实际时间来表达。
If you hadn't watched TV yesterday, you wouldn't be so sleepy now.如果你昨天不看电视，你现在也就不会这么困了。（从句yesterday说明过去，主句now说明现在）
If they had left home early this morning, they would arrive in half an hour.如果他们今天一早就离开家的话，再过半小时他们就该到了。（从句说明过去，主句说明将来。）
If you hesitated this moment, you might suffer in the future.如果你此刻犹豫不决，你将来会吃苦头的。（从句说明现在，主句说明将来）
注意：
在很多情况下，我们也可以用was来代替当主语是第一人称或第三人称单数时的were。
If were here tomorrow...
也可以说成：If he was here tomorrow...
I wish I were a bird.
也可以说成：I sish I was a bird.
但倒装句型中的were不可被was来替换。
Were I in your position,I would not do it.如果我处在你的位置，我是不会干这件事的。
E．含蓄条件句
非真实条件句中的条件从句有时不表达出来，只暗含在上下文中，这种句子叫做含蓄条件句。含蓄条件句大体有三种情况：
1．条件暗含在短语中
He would not get such a result without your help.没有你的帮助，他就不会有今天的成果。(条件暗含在介词短语without your help中)
But for you, I could not be recovered so soon.要不是有你，我就不会恢复得这么快。(条件暗含在But for you中)
This same thing, happening in the past, would lead to a disaster. 同样的事，如发生在过去，就会酿成大祸。(条件暗含在分词短语happening in the past中)
He must have been there, or he never could know the place so well. 他一定是去过那儿，否则他绝不会对那个地方如此熟悉。(暗含条件是连词or)
2．条件可根据上下文推理出
It would do you no good.这可能会对你没好处。(条件可能是if you should give up the job如果你放弃这项工作的话)
They could have won. 他们本来是会赢的。(条件可能是if they had been patient如果他们有耐心的话)
Such mistakes could have been avoided.这种错误完全能避免。（条件可能是if you had been more careful如果你更加小心一点的话）
Why didn't you tell me about it I should have helped you.为什么你不告诉我？我会帮助你的。（条件可能是if you had told me about it如果你当时告诉我的话）
--- Did you go to see him yesterday你昨天去看他了吗？
--- I would have, but someone dropped over to my house for a visit.原想去的，但有人到我家来玩了。（条件是if no one had dropped over to my house for a visit如果没人到我家来玩的话）
在书面语中，非真实条件句中有were, had, should时，可以省略if，而把were, had, should放在主语前，用倒装结构。
Were it necessary, I might go without delay.如果需要的话，我可以立即去。（= If it were necessary......）
Had you taken my advice, you wouldn't have failed in the exam.你要是听了我的建议，就不会考试不及格了。（= If you had taken my advice......）
Should I have time, I would call on her.要是有时间，我就去看她。（= If I should have time......）
D．错综条件句
虚拟条件句中的主句和从句涉及的动作发生的时间不一致，这时主句和从句的谓语形式应按照各自动作发生的实际时间来表达。
If you hadn't watched TV yesterday, you wouldn't be so sleepy now.如果你昨天不看电视，你现在也就不会这么困了。（从句yesterday说明过去，主句now说明现在）
If they had left home early this morning, they would arrive in half an hour.如果他们今天一早就离开家的话，再过半小时他们就该到了。（从句说明过去，主句说明将来。）
If you hesitated this moment, you might suffer in the future.如果你此刻犹豫不决，你将来会吃苦头的。（从句说明现在，主句说明将来）
注意：
在很多情况下，我们也可以用was来代替当主语是第一人称或第三人称单数时的were。
If were here tomorrow...
也可以说成：If he was here tomorrow...
I wish I were a bird.
也可以说成：I sish I was a bird.
但倒装句型中的were不可被was来替换。
Were I in your position,I would not do it.如果我处在你的位置，我是不会干这件事的。
E．含蓄条件句
非真实条件句中的条件从句有时不表达出来，只暗含在上下文中，这种句子叫做含蓄条件句。含蓄条件句大体有三种情况：
1．条件暗含在短语中
He would not get such a result without your help.没有你的帮助，他就不会有今天的成果。(条件暗含在介词短语without your help中)
But for you, I could not be recovered so soon.要不是有你，我就不会恢复得这么快。(条件暗含在But for you中)
This same thing, happening in the past, would lead to a disaster. 同样的事，如发生在过去，就会酿成大祸。(条件暗含在分词短语happening in the past中)
He must have been there, or he never could know the place so well. 他一定是去过那儿，否则他绝不会对那个地方如此熟悉。(暗含条件是连词or)
2．条件可根据上下文推理出
It would do you no good.这可能会对你没好处。(条件可能是if you should give up the job如果你放弃这项工作的话)
They could have won. 他们本来是会赢的。(条件可能是if they had been patient如果他们有耐心的话)
Such mistakes could have been avoided.这种错误完全能避免。（条件可能是if you had been more careful如果你更加小心一点的话）
Why didn't you tell me about it I should have helped you.为什么你不告诉我？我会帮助你的。（条件可能是if you had told me about it如果你当时告诉我的话）
--- Did you go to see him yesterday你昨天去看他了吗？
--- I would have, but someone dropped over to my house for a visit.原想去的，但有人到我家来玩了。（条件是if no one had dropped over to my house for a visit如果没人到我家来玩的话）
