What difference will it make if he knows or not?

　　他知不知道有什么關系嗎？

　　Please let me know how many are coming, if any.

　　請告訴我，如果有人要來的話，有多少？

　　That was a disaster if ever there was one!

　　那確實是場災難！

　　Put your hand up if you know the answer.

　　知道答案就舉手。

　　If you love each other, why not get married?

　　要是你們彼此相愛，干嗎不結婚呢？

　　If you don't believe me, go and see for yourself!

　　要是不信我說的，你自己去看看！