[求助]as when是什么意思？

出自XDF补充材料，虽然选对了（答案为E），但还是想弄清楚E选项中的AS WHEN是什么意思？怎么用法呢？

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

语法NN来帮帮我吧