1. Blotchy skin is a symptom of many skin diseases.
    皮肤上出现污斑是许多皮肤病的症状。

2. The riot can be considered a symptom of political instability.
    这次暴动可看作是政治上不稳定的征兆。

3. Now the snag in this sort of anecdote is of course that one cannot distinguish cause and effect. Was the noise a cause of the illness, or were the complaints about noise merely a symptom?
    这类奇闻的疑难之处是无法区别因果关系。是噪音引起了（精神）病呢，还是（精神）病的症状之一是对噪音的抱怨？