牙颈部脱敏最好用（）
A.碘化银法
B.氨硝酸银法
C.氟化钠法
D.碘酚法
E.离子导入法
参考答案：C
新生儿出生时皮肤苍白，心率40次/分，无呼吸，四肢略屈曲，弹足底无反应，Apgar评分为（）
A.1分
B.2分
C.3分
D.5分
E.7分
When changing lanes, a driver should use his turning signal to let other drivers know ____ . [ ]
A. he is entering which lane
B. which lane he is entering
C. is he entering which lane
D. which lane is he entering
