1） 語(yǔ)氣：
陳述，疑問(wèn)，祈使，虛擬
2） 虛擬語(yǔ)氣：表示一種純?nèi)患傧氲那闆r或主觀愿望，動(dòng)詞需要用一種特殊形式。
形式分為三類(lèi)：現(xiàn)在虛擬語(yǔ)氣（動(dòng)詞用原形），過(guò)去虛擬語(yǔ)氣（動(dòng)詞用過(guò)去式，但動(dòng)詞be要用were），過(guò)去完成形式（動(dòng)詞用過(guò)去完成時(shí)）。有些情態(tài)動(dòng)詞，如should, would, might常用在虛擬語(yǔ)氣中。
3） 虛擬語(yǔ)氣在條件句中的用法：
虛擬條件句：就是包含條件從句的句子。
條件句分為：
真實(shí)條件句——有些條件句是可能實(shí)現(xiàn)的。
虛擬條件句——有些條件句是純假象的句子。
If we leave now, we can still catch the train.
If I had enough money, I would buy a computer.
If you are waiting for a bus you’d better join the queue.
4) 表示現(xiàn)在和將來(lái)情況的虛擬條件句：
�、疟硎粳F(xiàn)在或?qū)?lái)的虛擬條件句——從句中的謂語(yǔ)（用過(guò)去式形式）；主句謂語(yǔ)（would+動(dòng)詞原形）
If I had a map I would lend it to you.
If you left your bike outside, someone would steal it.
If I were you I’d plant some trees round the house.
注：If I were you句中，were不能改成was,但在第三人稱(chēng)單數(shù)后用was也可以。如：
If Helen were(was) here how nice it would be!
�、浦骶渲^語(yǔ)有時(shí)也可以由might, could構(gòu)成。
If I could type, I might save a lot of time.
If he had a permit he could get a job.
�、窃跅l件句從句中有時(shí)還可以用were to +動(dòng)詞，或should+動(dòng)詞。
If he were (was) to resign, who would take his place?
If I should be free tomorrow, I will come to see you.
⑷在某些條件從句中（如were to +動(dòng)詞，should+動(dòng)詞），if有時(shí)可以省略，這時(shí)語(yǔ)序要改為倒裝。
Were I Tom, I would refuse.
Were I in your shoes I would let him know what I thought of him.
Should she be interested, I’ll phone her.
�、蓮木溆袝r(shí)可以用If it were not for這種句型，表示“若不是”。
If it were not for your help, we would be in serious trouble.
陳述，疑問(wèn)，祈使，虛擬
2） 虛擬語(yǔ)氣：表示一種純?nèi)患傧氲那闆r或主觀愿望，動(dòng)詞需要用一種特殊形式。
形式分為三類(lèi)：現(xiàn)在虛擬語(yǔ)氣（動(dòng)詞用原形），過(guò)去虛擬語(yǔ)氣（動(dòng)詞用過(guò)去式，但動(dòng)詞be要用were），過(guò)去完成形式（動(dòng)詞用過(guò)去完成時(shí)）。有些情態(tài)動(dòng)詞，如should, would, might常用在虛擬語(yǔ)氣中。
3） 虛擬語(yǔ)氣在條件句中的用法：
虛擬條件句：就是包含條件從句的句子。
條件句分為：
真實(shí)條件句——有些條件句是可能實(shí)現(xiàn)的。
虛擬條件句——有些條件句是純假象的句子。
If we leave now, we can still catch the train.
If I had enough money, I would buy a computer.
If you are waiting for a bus you’d better join the queue.
4) 表示現(xiàn)在和將來(lái)情況的虛擬條件句：
�、疟硎粳F(xiàn)在或?qū)?lái)的虛擬條件句——從句中的謂語(yǔ)（用過(guò)去式形式）；主句謂語(yǔ)（would+動(dòng)詞原形）
If I had a map I would lend it to you.
If you left your bike outside, someone would steal it.
If I were you I’d plant some trees round the house.
注：If I were you句中，were不能改成was,但在第三人稱(chēng)單數(shù)后用was也可以。如：
If Helen were(was) here how nice it would be!
�、浦骶渲^語(yǔ)有時(shí)也可以由might, could構(gòu)成。
If I could type, I might save a lot of time.
If he had a permit he could get a job.
�、窃跅l件句從句中有時(shí)還可以用were to +動(dòng)詞，或should+動(dòng)詞。
If he were (was) to resign, who would take his place?
If I should be free tomorrow, I will come to see you.
⑷在某些條件從句中（如were to +動(dòng)詞，should+動(dòng)詞），if有時(shí)可以省略，這時(shí)語(yǔ)序要改為倒裝。
Were I Tom, I would refuse.
Were I in your shoes I would let him know what I thought of him.
Should she be interested, I’ll phone her.
�、蓮木溆袝r(shí)可以用If it were not for這種句型，表示“若不是”。
If it were not for your help, we would be in serious trouble.
