现在你对于第三周的课程应该能够轻松面对了，是时候进入第四周的内容。 和第上周一样，参照同一列的指引进行训练。

Week 3 is now comfortably behind you and it's time to start Week 4. Continue by following the same column of exercises as you did last week.

youdao

We'll talk about cell culture engineering during Week 4, how do you maintain cells in culture, what are the limits of this.

第四周我们会探讨细胞培养工程,人们如何在培养基中维持细胞的存活,这种方法的局限性是什么

耶鲁公开课 - 生物医学工程探索课程节选

This is the end of week four.

这个第四周最后一次课。

哈佛公开课 - 计算机科学课程节选

Alright, welcome back to CS50, this is the start of week 4.

欢迎来到CS50学堂，这是第四周的课程。

哈佛公开课 - 计算机科学课程节选