早期牙龈炎症较轻但牙周袋常见于( )
A.单纯性牙周炎 B.咬合创伤 C.快速进展性牙周炎 D.青春前期牙周炎 E.青少年牙周炎
参考答案:E
—Do you like this T-shirt?
—No, I don’t.
— ?
—Oh, it is a nice T-shirt. I like it.
A.How about this one?
B.What color do you want?
C.Do you have a T-shirt?
D.How are you?
已知噪声源1的声压级为80dB、噪声源2的声压级也为80dB,则两个噪声源叠加后的声压级为( )。
A.(A) 160dB
B.(B) 80dB
C.(C) 85dB
D.(D) 83dB