2009年5月全国计算机软考网络工程师练习(18)

 　●In the following essay，each blank has fourchoices．Choose the best answer and write down on thean，swer sheet．
　　Microwave communication uses(1)frequency radio waves that travel instraighdine sthroughthe air．Because the waves cannot(2)with the curvature of the earth，they can be (3)onlyover short distance．Thus，microwave is a good(4)for sending data between bulldingsin a city or on a large college campus．For longer distances，the waves must berelayed by means of"dishes"or (5)．These can be installed on towers，highbuildings，and mountain tops．
　　(1)A．high
　　B．10w
　　C．1ong
　　D．short
　　(2)A．reflex
　　B．distort
　　C．bend
　　D．absorb
　　(3)A．transmitted
　　B．transformed
　　C．converted
　　D．delivered
　　(4)A．material
　　B．equipment
　　C．medium
　　D．channel
　　(5)A．repeaters
　　B．radars
　　C．telephones
　　D．antennas