牙髓感染途径包括 （）
A.牙本质小管暴露
B.牙髓暴露
C.牙周袋途径
D.深龋
E.血源感染
参考答案：A, B, C, D, E
—I have ______read the novel. How about you.
---I haven’t read it ______.
A. yet ,already , B. already before . C. already yet .
