问题
选择题
"The ground is wet." "Yes, didn't you know? ______for the last 20 minutes."
A．It's raining
B．It was raining
C．It's been raining
D．It has rained
答案
答案：C
时间状语for the last 20 minutes，表示的是过去的一段时间里完成的动作持续到现在并有可能继续下去，动词的时态应用现在完成进行时。故选C。