氟的防龋机制不包括
A.降低釉质的溶解性
B.促进再矿化
C.杀灭致龋菌
D.抑制细菌酶活性
E.影响牙齿外形
参考答案:C
一I have a favour to ask you.
一 .
A.Go ahead
B.It’s a pleasure
C.Help yourself
D.Ask,please