If it were not for ……
结构︰if it were not for+名词/子句，主词+would/should 等+原形动词…
说明︰此句型意为“若非(有)…”。此类句构专门用於表示与现在事实相反的。亦可用“but for+”或“without+”代替。were 可以提前，省略 if，如例句 it were not for his presence，I would punish you.要不是他在场，我会处罚你的.。
But for your advice,I should have failed.要不是你的忠告，我会失败的。
But for music (=Were it not for music),life would be dull.要不是音乐，人生会很无聊。
If it were not for oxygen and nitrogen in the air,no man could live on the earth.大气中如果没有氧和氮，人就无法生存於地球了。
Without air,all living things would die.若非空气，所有的生物都会死亡。
Without newspaper,we would get behind the times.要不是报纸，我们都赶不上时代了。
I should be lonely,were it not for the birds and the flowers.我会寂寞，若非有鸟也有花。
Were it not for his help,I could not finish the work.若非有他的帮助，我就不能完成这件工作。
Were it not for science,we could not live a comfortable live.若非科学，我们无法过着舒适的生活。
If it had not been for ……
结构︰if it had not been for+名词/子句，主词+would/should 等+原形动词…
说明︰此句型意为“若非(有)…”。此类句构专门用於表示与过去事实相反的。If it had not been for his help，I should have failed.如果没有他的帮忙，我应该已经失败。
Had it not been for your timely help,our company would have been on the verge of bankruptcy.若非你及时伸出援助之手，本公司将会濒临破产的边缘。
If it had not been for these experiments,the improvement of the machine would have been impossible.要不是这些实验，这部机器也许就不可能改良了。
Had it not been for the kind guide,I might have got lost in the mountains.要不是这位好心的向导，我可能就在山中迷路了。
If it had not been that he was here,I would have punished you.要不是他在场，我当时就会处罚你。
