总结下虚拟语气的倒装用法（虚拟语气倒装的三种情况）

有时可将条件从句的连词if省略，但此时应用倒装句型，即把从句中的 等提到句首：

If he should fail，he would kill himself. →Should he fail，he would kill himself. 万一失败，他就知会自杀。

If I were you，I would do it at once. →Were I you，I would do it at once. 假若我是你，我道就会马上做。

If I could do it，I would. →Could I do it，I would.

If I could do it，I would.

→Could I do it，I would.

要是我能做此事，我一定会做。

If he had seen you yesterday，he would haveasked you about it.

→Had he seen you yesterday，he would haveasked you about it.

他昨天要是看到了你，他就会问你这事了。

Were I Tom,I would refuse. 如果我是汤姆，我会拒绝。

Should it be necessary,I would go. 假若有必要，我会去的。

Had it not been for the bad weather we would have arrived on time. 若不是天气坏，我们就准时到达了。

【注】

① 若条件从句为否定句，否定词not应置于主语之后，而不能与were,should,had 等缩略成Weren’t,Shouldn’t,Hadn’t而置于句首。

② 有时省略if后提前的had不是助动词：

Had I time,I would come. 假若我有时间，我会来的。(=If I had time…)

考题：

__________ your address，I would have written to you.

A. Did I know B. Were I to know

C. Had I known D. If I should know

此题应选 C。这是虚拟语气的倒装形式。当虚拟条件句中含有 were，had，should，could等动词时，可以将if省略，然后将 were，had，should，could 等词移至句首。

顺便说一句，移至句首的 had不一定是助动词，如果是实义动词也可倒装：

If he had money，he would buy a car.

→Had he money，he would buy a car.

他要是有钱，他就会买一辆小车。