题目内容：

We were delayed by ( ). 1.a heavy traffic 2.heavy traffic 3.some heavy traffic 4.traffic being heavy
正确答案选择3.这题我看不懂.为什么选择3呢?

优质解答

对的
heavy traffic 为不可数,可排除1并确定3
这个要加冠词的话,应该是 the heavy traffic 或者the traffic being heavy （动名词的复合结构）,因为是特指这一次
选3