WHO牙周状况评价标准中牙结石平均检出区段数等级为中等的范围是
A.2.0~3.0
B.1.6~2.0
C.1.0~2.0
D.2.6~3.5
E.3.0~4.0
参考答案:D
—Have you ever _______ Paris before?
—Not yet. But I've planed to go there next month.[ ]
A. been with
B. been in
C. been to
D. gone to
对管电压选择的叙述,错误的是
A.管电压表示X线的穿透力
B.管电压控制照片影像对比度
C.管电压升高,摄影条件宽容度增大
D.高千伏摄影,光电效应增加
E.高千伏摄影,在有效消除散射线情况下,影像细节可见度增大