已知噪声源的声压级为=100dB,另一个噪声源的声压级为=98dB,则两个噪声叠加后的声压级为( )dB。
A.198
B.99
C.102.2
D.110
参考答案:C
在Visual FoxPro中表达式(1+2^(1+2))/(2+2)的运算结果是()。
The seller should lodge any claim for this consignment against the sellers( ) 30 days ( ) arrival of the goods.
A.within, in B.within, afterC.after, in D.after, on