Could you tell me ________? [ ]

A. what's his name

B. when did he study

C. how I can get to the bus station

D. if I have been to the Great Wall

咀嚼运动中产生的自洁作用不是指

A．加强唾液分泌量
B．唾液冲洗附着于牙齿及口腔的食物残渣
C．牙齿邻面之间的摩擦
D．食物与牙齿发生摩擦
E．发现混于食物中误入口腔的异物