单选题
According the experts, when headset sound reaches 110 decibcls, it can be used at most for ______.
A) one hour C) two hours
B) half an hour D) three hours
A、
According the experts, when headset sound reaches 110 decibcls, it can be used at most for ______.
B、
one hour
C、
half an hour
D、
two hours
E、
three hours
【正确答案】
B
【答案解析】
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