▲suppose本来是动词，supposing本来是现在分词，但它们有时可用作连词，引导条件状语从句，其意为“假若”“如果”等；此时主句通常为疑问句。如：
Supposing he can’t come, who will do the work? 假使他不能来，这工作谁做?
Supposing he does not come, shall we go without him? 如果他没来，我们可不可以不带他去?
Suppose you were given a chance to study in America, would you accept? 假如给你一个到美国学习的机会，你会接受吗?
Suppose [Supposing] (that) we miss the train, what shall we do? 假如我们误了火车，我们应该怎么办?
▲suppose和supposing引导条件状语从句的区别：suppose用作连词引导条件状语从句时必须置于主句之前，但supposing用作连词引导条件状语从句时，则可置于主句之前，也可置于主句之后。如：
We’d love to come and see you on Saturday, supposing I don't have to work that day. 我想星期六来看你，假若那天我不上班的话。