Actually, the view of vectors we take nowadays is that vectors are associated with a pair of numbers which, on the rotation of axes, transform like this.

实际上,今天我们讲矢量所用的观点是,矢量是和一组坐标值相对应的,在坐标轴旋转的过程中像这样变换

耶鲁公开课 - 基础物理课程节选

so it's a 250-person class, but we have a group of 50 that we go around with quite a bit.

这是一门250人的课，但是我们组成50人一组一起学习。

跟校友们的关系 - SpeakingMax英语口语达人

You just say that arbitrarily this group, the reference group, let's say the group with the lowest weights, or the lowest cholesterol or anything, you say their risk is one, and then you look to see how everybody else's risk is compared to that.

可以随意地设定一个群组,作为参照组,我们可以假设是体重最低的一组,或者胆固醇水平最低的一组或者其他,将参照组的风险设为1,然后就可以比较参照组与其他组的风险

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选