Had he followed the doctor’s advice， he might be alive now.
当时他要是听了医生的建议，现在可能还活着。
I wish ... V-ed ...
结构︰I wish (that) 主词 动词过去式/过去完成式(had 过去分词)…
说明︰I wish 之后以 that <子句>为<受词>时，该<子句>的<动词>一定要用<假设语气>：若<动词>用过去式，表示与现在事实相反的愿望；若用<过去完成式>，则表示与过去事实相反的愿望。“I wish that-<子句>”的<句型>也可用“I would rather that-<子句>”取代。而 I hope 之后以 that <子句>做<受词>时，该<子句>用一般<时态>。
I wish there were meadows and lambs. 但愿有草地与小羊。
I wish I were as tall as you. 但愿我像你一样高。
I wish he could tell us. 但愿他能告诉我们。
I wish (=I would rather) he could come tomorrow. 但愿他明天能来。
I wish you had not been caught in the rain yesterday. 但愿昨天你们没有淋到雨。
I wish you had not told the truth. 但愿你没有说实话。
I wish I had known you ten years ago. 真希望十年前就已经认识你。
If only V-ed
结构︰If only 过去式/过去完成式
说明︰此句型意为“要是…就好了。”用过去式，表示与现在事实相反；若用<过去完成式>，则表示与过去事实相反。
If only I had a rich father. 要是我有个有钱的爸爸就好了。
If only he had been here. 要是他当时在这儿就好了。
If only I had another chance. 要是我再有一次机会就好了。
... as if/as though ...
结构︰…as if/as though…现在式/过去式/过去完成式
说明︰此句型意为“彷佛…；好像…一样”。as if，as though 是<副词><连接词>，引导<副词子句>。<子句>中，可用现在式，以表示事实；也可用过去式或<过去完成式>，分别表示与现在或过去事实相反的<假设语气>。