— I am sorry to tell you that you failed the exam.
— Well. I've already known it.
A:didn't pass
B:didn't have
C:didn't know
一个路口的红绿灯,红灯的时间为30秒,黄灯的时间为5秒,绿灯的时间为40秒,当你到达路口时,不需要等待就可以过马路的概率为( )