采购中（）认为，供应商离自己越近，运输费用就越低，机动性就越高，协调节器沟通就越方便.
A.适量原则
B.适地原则
C.适时原则
D.适价原则
参考答案：B
I was on the highway when this car went past followed by a police car. They ______ at the speed of
150 kilometers an hour at least. [ ]
A. should have been driving
B. must have been driving
C. could have driven
D. would have driven
试述高填方渠段不均匀沉陷原因。
