The traffic is jam.

问题描述:

The traffic is jam.

不对: the traffic is jammed = it's rush-hour time

不对,倒有一个词组是 traffic jam意思是交通堵塞,是可数名词

没有错,

错!应该说there's a traffic jam.

不对!
traffic jam
n.
塞车,交通拥塞 固定词组
如果你非要这样说就
The traffic is jammed.