分贝的定义是()。
A.两个声强的比值
B.两个声强之和
C.声波散射量
D.声波的频率
E.两个声强之差
参考答案:A
解析:强度比的对数值通常称为声强级,分贝为声强级的单位。
The second-hand car Tom bought was very cheap. ______ it was in excellent condition.
A.Even
B.Although
C.Besides
D.While
阿米巴病排包囊者可选用
A.氯喹B.依米丁C.甲硝唑D.二氯尼特E.巴龙霉素