One group changed the classroom while studying, the other didn’t.

一组在读书的时候换教室，另一组则不。

One group changed the classroom while studying, the other didn't.

一组一边学习一边换教室，另一组没有。

In the nineteen seventies, the group changed record companies and shortened their name to the Jacksons.

1970年代，该组合更换了唱片公司并将组合名字改为Jacksons。

The blots of shade and flakes of light upon the countenances of the group changed shape and position endlessly.

一片片阴影、一点点光斑，在那群人脸上不停地变换着形状和位置。

The group changed its name later to Diana Ross and the Supremes.

该团体后来更名为戴安娜罗斯和至尊乐队。

The al-Shabaab terrorist group changed that.

青年党恐怖组织改变了这一点。

The basic SIR model makes some assumptions about how the fraction of people in each group changes over time, based on real-world observations.

基本的 SIR 模型基于真实世界的观察，对每组中的人口比例如何随时间变化做出一些假设。

Then, we step ahead in time, and the proportions in each group change according to the model's equations: some susceptible people become infected and some infected people become " removed" , by recovering or dying when enough time passes.

随着时间的推移，每一组中的比例根据模型的方程式而变化：一些易感者被感染，一些被感染的人在足够长的时间后通过康复或死亡而被“转归”。