随着距探头的距离而变化的是（）。
A.横向分辨力
B.频率
C.轴向分辨率
D.空间脉冲长度
参考答案：A
Could it be in the room __________ we had a talk last night__________ you left your keys? [ ]
A. that ; where
B. in which ; where
C. where ; that
D. where ; where
按标准的性质分类，标准可分为哪些？
