【题目】The cost of living in big cities ________ steadily for many years，and it has led some youths to drop out of the big city race.
A. is climbingB. is being climbed
C. has been climbingD. has been climbed
在线课程【答案】C
【解析】
考查时态。句意：许多年以来，大城市的生活费用稳步增高，这导致许多年轻人逃离了大城市。表示一个从过去开始但仍在进行的动作，用现在完成进行时，故选C。