With multiple causes and no one solution, this pollution crisis will not be easy to solve.

由于污染由多种原因导致却没有一个解决方案，这一污染危机不会容易解决。

It was thought to be certain neuro-transmitters and there have been multiple other causes that have been suggested.

一直认为它是某种神经递质，病因也是多种多样。

But what if we could find one therapy that could treat multiple causes?

但是，如果我们能找到一种可以治疗多种原因的疗法呢？

But for a disease like AMD, where there's multiple possible causes, it's just not as useful at this point in time.

但对于像 AMD 这样有多种可能原因的疾病，它在这个时间点就没有那么有用了。