想像一下如果已经爆发了麻疹，而消息是在爆发后的三个月后才传到我们这里。

Imagine if we have an outbreak of measles and the information is relayed to us three months after the outbreak.

youdao

如果已经接收到数据，则不需要其他调用。

If data is already received, there is no need for an additional call.

youdao

如果已经太晚了，我们很乐意听到的细节。

If it's too late, we would love to hear the gory details.

youdao

OK, important -- if you are part of this group here think about it and make sure you understand that.

好的，这很重要，如果刚才你选了可逆过程,请好好想想并且保证已经理解了这个问题。

麻省理工公开课 - 热力学与动力学课程节选

For example, if you are running behind schedule and you really must be moving to your next appointment,

例如，如果你已经比计划的时间晚了，不得不马上赶赴下一场约会的时候，

have to 课堂 - SpeakingMax英语口语达人

I didn't expect it to do this. If you understand why it did what it did, you're half way there.

这样运行的啊，如果你能弄明白为什么,它这么运行，你已经完成了差不多一半了。

麻省理工公开课 - 计算机科学及编程导论课程节选