不用叫，你说的话我听得很清楚。

No need to yell. I can hear you clearly.

youdao

哦，好了，我可以吃东西了，不用叫医生。

Oh well, I'm ready to eat. No need call the doctor.

youdao

不——不要紧。这也许慢慢会过去的，不用叫任何人来。

No-never mind. It'll be over by and by, maybe. Don't call anybody.

youdao

Here's a way that you can do it in a test tube without using any cells by this process called Polymerase Chain Reaction.

但有一个方法可以让你在试管中完成,不用细胞,这个方法叫聚合酶链式反应

耶鲁公开课 - 生物医学工程探索课程节选