4．unless能作为介词使用.相当于except.而if-not不可以. Nothing will come out of it unless disaster. 这种事除非引起灾祸之外不会有什么结果. C．so long as, as long as, on condition that 这几个短语意思差不多.都表示只要.条件是--. As/So long as we don't lose heart, we'll find a way to overcome the difficulty. 只要我们灰心.我们就能找到克服困难的方法. You may use the room on condition that so long as you clean it afterwards. 只要你用完后打扫干净.你就可以使用这个房间. D．in case in case 既引导目的状语从句.也可以引导条件状语从句.等于if it happens that. In case I forget, please remind me of my promise. 如果我忘了.请提醒我所做的承诺. Send s a message in case you have any difficulty. 万一你有什么困难.请给我们一个信儿. E．providing, provided that, supposing, suppose that, given that 这几个短语意思相近.有如果.只要.假如等意思. Given that they are inexperienced, they've done a good job. 考虑到他们缺乏经验.他们的工作已做得很好了. provided Providingwe invite him, he would surely come to dinner. 假如我们邀请他的话.他肯定会来吃饭的. Suppose/Supposing we can't get enough food, what shall we do 假设我们弄不到足够的食物.那我们怎幺办? 【查看更多】
