问题 填空题

( )是指在通信过程的任意时刻,信息既可由A传到B,又能由B传到A,但只能有一个方向的传输存在。

答案

参考答案:半双工

解析: 半双工是指在通信过程的任意时刻,信息既可由A传到B,又能由B传到A,但只能由一个方向上的传输存在。全双工是指在通信的任意时刻,线路上存在A到B和B到A的双向信号传输。在全双工方式下,通信系统的每一端都设置了发送器和接收器,因此能控制数据同时在两个方向上传送。

问答题
完形填空
It was a sunny day. A city man was driving along a country road with a new wagon(马车)and a beautiful pair of horses. He didn’t pay a lot of  16  to where he was going. Pretty soon he  17_ that he was lost, but he continued to drive, expecting to re-find his way or to  18  someone who could tell him how to get back to the  19  .
It was a long 20 road. For many __21__ he kept on driving. When it was almostdark ,he saw in a field a tall  22  ploughing(犁地) the land. He stopped his   23 team of horses near the fence and called out,“Hello,farmer.”
“Hello,yourself,”the farmer___24____,still ploughing .
“Where does the horse go?”he asked without knowing his language mistakes.
“I haven’t seen it go anywhere. It   25  stays right where it is,”said the farmer,withoutstopping his work.
“How far is it to the next town?” said the city man,speaking a little more   26  .
“Don’t know. I never    27 it,” replied the farmer. By this time the city man was getting 28 .“What do you know?You’re the biggest fool I ever saw.”
Finally stopping, the farmer turned and looked for a long time  29  at the city man. Then he said,“Maybe I don’t know much.   30  I am a fool. But at least I’m not lost!” 
小题1:
A.signsB.ordersC.attentionD.direction
小题2:
A.realizedB.recognizedC.acceptedD.received
小题3:
A.missB.meetC.lookD.lose
小题4:
A.townB.countryC.capitalD.village
小题5:
A.lonelyB.busyC.dirtyD.crowded
小题6:A seconds     B. minutes     C hours          D years
小题7:
A.driver B.policemanC.farmerD.worker
小题8:
A.strongB.tiredC.weakD.tiring
小题9:
A.askedB.demandedC.repliedD.ordered
小题10:
A.alwaysB.oftenC.sometimesD.seldom
小题11:
A.politelyB.friendly C.loudlyD.angrily
小题12:
A.judgedB.measuredC.sawD.studied
小题13:
A.sadB.lovelyC.friendlyD.angry
小题14:
A.gladlyB.immediatelyC.silentlyD.excitedly
小题15:
A.GenerallyB.FortunatelyC.CertainlyD.Perhaps