but if引导什么从句

　　We don't actually need it on Tuesday, but if it arrives by then, so much the better.

　　实际上我们星期二并不需要它，但如果那时能到就更好。

　　He said they did not want war — but if attacked they would fight to the death

　　他说他们不希望有战争——但一旦遭到攻击，定会战斗到底。

　　But if you arm the police won't more criminals go armed?

　　但是，如果你给警察配备武器，难道不会出现更多配备武器的罪犯吗？

　　This will cost money, but if social inclusion is to succeed, it must be spent.

　　这是需要花钱的，但是要想社会融入行动取得成功，这笔钱就必须得花。

　　But if he does this, he may hasten the collapse of his own country.

　　但是如果他这样做，就有可能加速自己国家的崩溃。