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问题 单项选择题

短时间暴露在强噪音环境下感觉声音刺耳、听阈上升10～15dB，迅速离开噪音环境数分钟后可完全恢复的现象，称之为（）.

A.听觉适应

B.听觉疲劳

C.失音症

答案

参考答案：A

单项选择题

急性腹膜炎始终存在的主要体征是（）

A.两下肢屈曲状态

B.腹胀明显

C.发热

D.肠鸣音消失

E.压痛和反跳痛
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单项选择题 共用题干题

Both bus and tree topologies are characterized by the use of multipoint (1).For the bus, all stations attach, through appropriate hardware (2) known as a tap, directly to a linear transmission medium, or bus. Full-duplex operation between the station and the tap allows data to be transmitted onto the bus and received from the(3). A transmission from any station propagates the length of the medium in both directions and can be received by all other  (4). At each end of the bus is a (5) , which absorbs any signal, removing it from the bus.

空白（4）处应选择（）

A.routers

B.stations

C.servers

D.switches
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