but for 表示“若不是”“要不是”“要是没有”时，通常要与虚拟语气连用，且通常放在句首——但也完全可以放在句末。如以下各句均摘自原版词典：

I would have been in real trouble but for your help. 要不是有你帮忙，那我可就倒大霉了。

I might never have got to university but for you. 要是没有你的话，我可能永远也上不了大学。

the owner would have died but for the prompt action of two ambulancemen. 要不是两名救护队员立即行动，业主可能早就死了。

Spurs could have had several goals but for some brilliant saves from John Hallworth. 要不是约翰·霍尔沃思几次精彩的扑救，热刺队原本可以射进好几个球。