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

，着时间的推移，感人数的减少相当于转归组人数的增加。

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

此时，易感人被感的速度与感者转归的速度完全相同。

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

但是有些人也会康复或死亡，这意味着着时间的推移，人们会从感转移到被转归。

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.

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

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.

在人们被感一段时间后，他们会转移到转归组，因为他们已经康复了，或者不幸的是，已经死了，不能再传播感了。

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.

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，一些被感的人在足够长的时间后通过康复或死亡而被“转归”。