引发牙髓感染的途径不包括（）
A.牙髓暴露
B.牙本质暴露
C.血源感染
D.牙周袋途径
E.正常咬合
参考答案：E
— How long_____like this?
— Three weeks! It's usual in here that rain_____without stopping these days of the year. [ ]
A. has it rained; pours
B. is it raining; is pouring
C. has it been raining; pours
D. does it rain; pours
简述微裂缝排烃模式
