平滑面龋的病损形态是
A. 烧瓶状,口大底小
B. 烧瓶状,口小底大
C. 三角形,底位于釉质表面
D. 三角形,底位于釉牙本质界(窝沟龋)
E. 浅碟状,口大底浅
釉质龋暗层的孔隙容积占釉质体积的
A. 0.1%
B. 1%
C. 2~4%
D. 5%
E. 25%
Listen to the following dialogue and answer the questions that follow. How many people were involved in the conversation?____________ people. (空格处请填入英文数字, 并注意句首字母大小写的要求。)
Listen to the following dialogue and answer the questions that follow. What is the most probable relationship between the speakers: teacher and student, doctor and patient or just friends? ______________.