[求助]新东方蓝皮书 主谓一致

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 statesmen 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

答案选E，可是主语单数的话broadcast不是应该加s吗？

主语怎么是单数？major networks是复数啊，如果要表达单数应该是each of the three major networks，each如果放在后面表示单数含义，但语法上仍然是复数

噢,这样啊~我以为有each就是单数。。。

谢谢了！