I wanted to introduce it to you so that if you don't haven't heard about this before you might want to read a little bit about this before we get to Chapter 5.

我想给你们介绍一下细胞膜,所以如果你没有,以前没听说过这个的话,也许你在学到第五章之前,要读一点关于这些的文献

耶鲁公开课 - 生物医学工程探索课程节选

Because your store might not do so good, if you just first open and no one has ever heard of you,

因为你的商店也许会没那么好。如果你是第一次开店，没有人听说过你的话，

想开精品店 - SpeakingMax英语口语达人

Because you've heard it so many times before.

因为也许你早就听说过很多回了。

What kind of 课堂 - SpeakingMax英语口语达人