—Why are you late Jim?—Because there a lot of traffic when I came here.A. isB. areC. was

问题补充：

—Why are you late, Jim?

—Because there a lot of traffic when I came here.

A. is

B. are

C. was

D. were

答案：

A. is

B. are

C. was

D. were

解析：本题考查There be句型的时态。根据句意：“—Jim，你为什么迟到？—因为当我来这儿时，有许多车辆。”，原因发生在过去，而且traffic是不可数名词，本题应用is的过去式was。故选C。