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问题 单项选择题

802.11a不支持的传输速率为

A．5.5Mbps

B．11Mbps

C．54Mbps

D．100Mbps

答案

参考答案：D

解析： 本题考查无线局域网标准IEEE 802.11的相关概念。802.11定义了使用红外、跳频扩频与直接序列扩频技术，数据传输速率为1Mbps或2Mbps的无线局域网标准。802.11b定义了使用跳频扩频技术，传输速率为1、2、5.5与11Mbps的无线局域网标准。802.11a将传输速率提高到54Mbps。目前还不能达到100Mbps，正确答案为选项D。

听力题

Henry found a job in a bookstore after he finished middle school. He wouldn't do anything but wanted to get rich. It was a cold morning. It _______ （snow） and there was thin ice on the streets. Few people went to buy the books and the young man had nothing  ______ （do）. He hated to read, so he watched the traffic. Suddenly he  ______ （see） a bag fall off a truck and it landed by the other side of the street. “It _____  （be） full of expensive things.” Henry said to himself. “I have to get it right now, or others  ______  （take） it away.” He went out of the shop and ran across the street. A driver saw him and began to whistle （鸣笛）， but he didn't hear it and went on  ______ （run）. The man drove to the side, hit a big tree and  ______ （hurt） in the accident. Two weeks later Henry was taken to court. A judge asked if he heard the whistle when he was running across the street. He said that something was wrong with his ears and he could hear nothing. “But you  ______  （hear） me this time,” said the judge. “Oh, I'm sorry. Now I can hear with one ear.” “ ______ （cover） the ear with your hand and listen to me with your deaf one. Well, can you hear me?” “No, I can't, sir.” “You  ______   （tell） lies. There is nothing wrong with either of your ears.” The judge said.
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单项选择题

患者，妊娠期间少量 * * 出血，色淡红质稀，小腹空坠而痛，腰酸，心悸气短，神疲肢倦，舌淡苔薄白，脉细弱略滑。应选用下列哪方（）

A.胎元饮

B.寿胎丸

C.三仁汤

D.滋肾育胎丸

E.当归散
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