完型填空：If you stand a short distance away from
2010-07-08 15:09阅读：
本题是2008年下半年学位英语教材第十单元的课后完型填空。
本题是2009年下半年学位英语教材第十单元的课后完型填空。
If you stand a short distance away from a high wall and shout, your voice sometimes comes, back to you as an echo. This happens because the 1.sound waves are reflected 2.off the wall. This is the principle of radar, 3.but instead of sound it is radio waves which are reflected. This 4.discovery was made a few years before the last war, 5.when radio waves from a transmitting station 6.were reflected back from a distant aeroplane.
It was realized 7.that if an apparatus could be devised to send out radio waves 8.all the time and record the 9.echoes from any approaching aeroplanes, it would be a wonderful method of defense in 10.war.
Scientists 11.set about solving the prob
本题是2009年下半年学位英语教材第十单元的课后完型填空。
If you stand a short distance away from a high wall and shout, your voice sometimes comes, back to you as an echo. This happens because the 1.sound waves are reflected 2.off the wall. This is the principle of radar, 3.but instead of sound it is radio waves which are reflected. This 4.discovery was made a few years before the last war, 5.when radio waves from a transmitting station 6.were reflected back from a distant aeroplane.
It was realized 7.that if an apparatus could be devised to send out radio waves 8.all the time and record the 9.echoes from any approaching aeroplanes, it would be a wonderful method of defense in 10.war.
Scientists 11.set about solving the prob