The room _____ as a laboratory for nearly two years till now.

The room _____ as a laboratory for nearly two years till now.
A、is used
B、was used
C、has been used
D、had been used
【正确答案】：C
【题目解析】：本题考查时态。句意：这个房间迄今为止已被当作实验室将近两年。从时间状语"for nearly two years till now"可知，句子的动作一直持续到现在，并且有可能继续下去，因此应该用现在完成时。