Car rental agencies a boom in business ever since new restrictions made it harder for people to buy an automobile in the capital.
A. has enjoyed
B. have been enjoying
C. are enjoying
D. enjoyed
网友回答
A. has enjoyed
(答案→)B. have been enjoying
C. are enjoying
D. enjoyed
解析：考察时态。本题的关键在于后面的ever since（自从）引导的时间状语从句，该时间状语常常与现在完成时连用。句意：自从新的限制让首都人民购买汽车变得更加困难，汽车租赁已经有了很快的发展。该句的主语是复数形式，故B正确。