折现率应高于（）
A、折旧率
B、折扣率
C、无风险利率
D、成新率
参考答案：C
Oh, this is really a big shop. Do you know when it _______?
A. built
B. was built
C. has built
D. has been built
推土机填沟或驶近边坡时注意什么？
