一、省略连词if
有时可将条件从句的连词if省略，但此时应用倒装句型，即将从句中的were, should, had 等提到句首。如：
Were I you, I would stay. 倘若我是你, 那我就留下。
Should I be free tomorrow, I will come. 万一我明天有空，我会来。
Had it not been for the bad weather we would have arrived in 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。如：
Had I time, I would come. 假若我有时间，我会来的。(=If I had time…)
二、省略从主语和动词be
若主从句主语一致，且谓语部分包含有动词be，通常可将主语和动词be省略。如：
If repaired earlier, the tractor would not have broken down. 要是早点儿修一下，拖拉机就不会抛锚了。(=If it had been repaired earlier…)
三、省略“it+be”
If necessary, I would send more farm-hands to help you. 如果需要的话我会派更多的民工去你。
四、省略整个条件从句
这样的省略通常需要借助一定的上下文，即省略条件从句后，所剩下的主句的意思在一定的上下文中意思是清楚的。如：
I might see her personally. It would be better. 我可以亲自去看她，这样好一些。(=…If I saw her personally, it would be better.)
