But you don't know that there is an easy one for you down at number four 4 if you haven't bothered to look at number four.

但是你不知道,在数字4的时候会有一个简单的题目,如果你没有尝试去看数字。

麻省理工公开课 - 固态化学导论课程节选

For those of you don't know what that is it's simply an instrument that counts radioactive particles in the air, and MIT now that you're at MIT, you'll all have a chance to see one first hand if you're ever in any of the labs, especially in the chemistry or bio labs.

不知道它是什么,它就是一个简单的,计算在空气中放射粒子数目的仪器,你们现在来了，如果你们在实验室里工作的话,尤其是化学和生物实验室，你们有很多机会亲手用到它。

麻省理工公开课 - 化学原理课程节选

Short answer is, I don't know.

一个简单的答案就是,我不知道

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