去除颈部及根面上附着的牙菌斑,最有效的机械法是
A.刷牙B.牙线C.牙签D.牙间刷E.橡胶按摩器
参考答案:D
________ he came in, I recognized him.[ ]
A. The moment
B. Shortly
C. Soon
D. Before long
公安机关的专政职能是用以对付一切违法犯罪人员的。( )