根据工业企业厂界噪声标准中，在居民文教区的夜间短促鸣笛的峰值等效声级LAeq为( )dB。
A．45
B．50
C．55
D．60
参考答案：D
_____ in the queue for half an hour, Tom suddenly realized that he had left his wallet at home. [ ]
A. To wait
B. Have waited
C. Having waited
D. To have waited
A．天然气
B．氢气
C．煤
D．石油
