采用高应度测桩的承载力时，只限于（）直径桩。
参考答案：中、小
— Your bike is very beautiful. How long ____you _____it? — Just two weeks.
A. have; bought B. did; buy C. have; had
高频探头的声束扩散角要比同直径低频探头的（）。
A.大
B.小
C.一样
D.任意
