At that moment, susceptible people become infected at exactly the same rate as infected people become removed.

此时，易感人群被感染的速度与感染者转归的速度完全相同。

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通过康复或死亡而被“转归”。

And finally there's the " removed" group, the people who have already had the disease and have either recovered and gained immunity or, sadly, died of it.

“转归人群”，他们已经患病，或者已经康复并获得免疫力，或者不幸地死于该疾病。

And, the decrease of the number of infectious people over time is equivalent to the increase in removed people.

并且，随着时间的推移，感染人数的减少相当于转归组人数的增加。

But some people will also be recovering or dying, which means people will move over time from the infected to the removed group.

但有些人也会康复或死亡，这意味着随着时间的推移，人们会从感染群体转移到被转归群体。

And Assumption Three: after people are infected for a while, they move to the removed group, since they've recovered, or sadly, died, and can't transmit the infection anymore.

在人们被感染一段时间，他们会转移到转归组，因为他们已经康复了，或者不幸的，已经死了，不能再传播感染了。