是虚拟语句例如：
1.If so, come early to the talk at 7.30pm by Jules Skye, a successful record producer.如果是的话，请早点来参加晚上7：30成功唱片制作人朱尔斯·斯凯的演讲。
2.If so, they can get on well with each other.如果是的话,他们可以相处得很好。
3.Do you have a knack for coming up with ideas? If so, we would love to hear from you.你有什么能想出好点子的诀窍吗？如果有，我们很愿意收到你的来信。
