单选题 I'm sorry I'm late, I was held up in a traffic ______.
A. block B. group C. jam D. bunch

【正确答案】 C
【答案解析】jam意为“塞满,阻塞”,traffic jam意为“交通阻塞”。A.block意为“障碍物”; D.bunch意为“束,捆”。