If the PSCO has clear grounds for carrying out a more detailed inspection, （）should be immediately informed of these grounds.

Would you mind if I turned the radio up?（）

We（）the distress signal on our own radio before the shore station relayed it to us.

When a vessel signals her distress by means of a gun or other explosive signal，the firing should be at intervals of approximately（）.

The radio waves used for radar are very short，only（）long.

（）is a radio receiver with ablity to sense direction of the incoming radio waves.

A radio determination system based on the comparison of reference signals with radio signals reflected,or retransmitted from the position to be determined,is（）.

Before GMDSS, if the radio officer on board is serious ill,（）.

Due to GPS roll over of the clock cycle，GPS receivers may give the wrong time and position or may lock up permanently on（）.

Practice 3　　BBC World Service is the world's biggest radio network, with 140 million listeners across the globe, broadcasting in 44 languages, heard on short-wave, medium-wave, FM and satellite. We have an ambitious plan for the brand new technology of Digital Broadcasting by Satellite, due to start next year. The appearance of the Internet has taken us broadcasters all by surprise. The Internet has enabled any radio station anywhere to become an international broadcaster with only a minor investment. Although its sound quality is far from perfect, it excels that of short-wave. Internet radio does not only mean competition but also great opportunities. The BBC is taking the Internet very seriously, for it's a cheap way of getting a reasonable quality signal to places in the even our short-wave transmitters can't adequately reach. Very recently, we launched “BBC On-Line”, which incorporates a 24-hour news service. And the users can hear programmes in Mandarin, Arabic, Spanish and Russian.

根据下面的文字资料回答 71～75 题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．第71题：文中（ 1 ）处正确的答案是（ ）。

When testing a Class A EPIRB you will know the EPIRB is working properly if you hear on 99.5 Mhz FM or any vacant frequency on a nearby AM radio（）.