[名师点津]　

　　若省略的条件句中的谓语动词是否定形式时，不能用动词的缩略形式。例如：

　　Were it not for the expense, I would go abroad now.(正)

　　Weren't it for the expense, I would go abroad now.(误)

　　[即时训练2]　句型转换

　　①If I were not so careless, I would not have lost my watch yesterday.

　　→ Were I not so careless, I would not have lost my watch yesterday.

　　②If I had known your telephone number yesterday, I would have telephoned you.

　　→ Had I known your telephone number yesterday, I would have telephoned you.

　　③If it should rain tomorrow, the work would be postponed for some days.

　　→Should it rain tomorrow, the work would be postponed for some days.

　　2．错综时间条件句

　　虚拟语气中，条件从句中谓语可以和主句中的谓语发生时间不一致，这时从句和主句要根据各自所发生的时间选用符合具体时间的虚拟语气形式。

　　If you had prepared in advance, you wouldn't be in such an awkward position now.

　　如果你事先作好准备， 现在就不至于那么被动。(从句表示过去，主句表示现在)

　　If I were you, I would have gone to her birthday party.

　　如果我是你，我就去参加她的生日宴会了。(从句表示现在，主句表示过去)

　　[即时训练3]　用括号内动词的适当形式填空

　　①If you had listened(listen) to me yesterday, you wouldn't be in such trouble now.

　　②If I were(be) you，I would have planted some trees around the house.

　　③If you hadn't watched(not watch) TV yesterday, you wouldn't be(not be) so sleepy now.

　　3．含蓄虚拟条件句

有时假设的情况不是以if条件从句表示，而是通过其他形式表现出来，这时被称作含蓄虚拟条件句，其主要用法如下：