（）an order for one thousand tons or more we grant a special discount of 10%.

（）is a space system using one or more artificial earth satellites.

（）is a space system using one or more artificial earth satellites.

In modern fathometers the sonic or ultrasonic sound waves are produced electrically by means of a(n)（）.

Microwave communication uses high-frequency(56)waves that travel in straightlines through the air. Because the waves cannot(57)with the curvature of the earth, they can be(58)only over short distance. Thus, microwave is a good(59)for sending data between buildings in a city or on a large college campus. For longer distances, the waves must be relayed by means of "dishes" or(60).These can be installed on towers, high buildings, and mountain tops.

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（ ）。

Ships carrying 15 or more seafarers and engaged in a voyage of more than three day’s duration shall provide separate hospital accommodation to be used（）.

● Insufficient （71）can cause a processor to work at 50% or even more below itsperformance potential.（71）

Insufficient(71)can cause a processor to work at 50% or even more below its performance potential.

If necessary to avoid collision or allow more time to（）the situation，a vessel shall slacken her speed or take all way off by stopping or reversing her means of propulsion．

A c（） sentence contains two or more clauses， one of which is incorporated in the other.

MODERATE WAVES，TAKING A MORE PRONOUNCED LONG FORM；MANY WHITE HORSES ARE FORMED.THIS sea condition is likely to be termed（）.