(1)条件从句中的谓语部分有were，should和had时，if有时可以省略，这时从句中的主语和谓语要用倒装语序。

　　Were I you，I would go with them.

　　如果我是你的话，我就跟他们一起去。

　　Should I have time，I would call on her.

　　我要是有时间就去看她。

　　(2)if it be not for...也是一种条件虚拟语气从句。

　　If it had not been for the help of our teacher, we should not have made so much progress.

　　如果没有老师的帮助，我们就不会取得这么大的进步。

　　If it had not been for me, you would not be free.

　　要不是我，你就不会自由。

　　Had it not been for his help，I wouldn't have succeeded.

　　如果没有他的帮助，我就不会成功。

　　注意：句中的if it weren't for.../if it hadn't been for... 相当于but for...，意为"多亏了......，要不是......"。这两个句型倒装时not总是在it之后，即were it not for.../had it not been for...。

　　(3)有些条件句中主句的谓语和从句的谓语表示的动作在时间上并不一致，这类句子称为错综时间条件句。

　　If you'd listened to me,you wouldn't be in such trouble now.如果你听了我的话，你现在就不会有这样的麻烦了。（过去→现在）

　　If I were you,I wouldn't have missed the movie last night.如果我是你，我就不会错过昨晚那部电影。（现在→过去）

　　If they had left home early,they would arrive in half an hour.要是他们早离开家的话，再过半个小时就该到了。（过去→将来）

　　If Monica should arrive today,she must have started three days ago.如果莫尼卡今天到达的话，那她一定是在三天前就动身了。（将来→过去）

(4)有时虚拟语气的条件是通过词或短语表示出来的。

　　There wouldn't be such modern industry without electricity (＝if there weren't electricity)．

　　倘若没有电，就不会有现代工业。

　　He is ill.Otherwise (＝if he weren't ill) he could come.

　　他病了，否则他会来。

　　A gentleman (＝If he had been a gentleman he) wouldn't have said so.

　　一位绅士是不会那样说话的。

　　Given more time (＝If we were given more time)，we would do it better.

　　再给些时间，我们会做得更好。

　　(5)有些句子虽不含条件从句，但仍用虚拟语气，这种句子称为含蓄条件句。

　　I would do anything for her.

　　我愿意为她做任何事。

　　We could have won the battle.

　　我们本来可以赢得那场比赛。