He resolutely refused to speak English unless forced to.
除非被逼迫，他堅決拒絕說英語。
Why did you need a room unless you were up to something?
除非你要搗什么鬼，不然為什么需要一個房間呢？
Recovery can't be sustained unless more jobs are created.
除非有更多的工作機會被創(chuàng)造出來，否則復(fù)蘇無法保持下去。