19. Although it claims to delve into political issues, television can be superficial such as when each of the three major networks broadcast exactly the same statement from a political candidate.

(A) superficial such as when each of the three major networks

(B) superficial, as can sometimes occur if all of the three major networks

(C) superficial if the three major networks all

(D) superficial whenever each of the three major networks

(E) superficial, as when the three major networks each

这道题的答案E是没问题，可是在这里对as when不太明白。这里的as ：1，是表示举例吗？（such as 不能接句子只能接短语所以用as来表示举例？） 2，是代前面一个句子-television can be superficial？但是这样我觉得as不就多余了？直接说television can be superficial when......不就行了？干吗硬生生扯个as在中间，怪怪的。那位大虾能指教一下吗？不胜感激