更多"Although they plant trees in this a"的相关试题:
[单项选择]Though people plant many trees in this area every year, the top of some hills is still ______.
A) open C) empty
B) bare D) blank
[简答题]How many earthquakes every year？
[填空题]Earthquake
Every year earthquakes are responsible for a large number of deaths and a vast amount of destruction in various parts of the world. Most of these damaging earthquakes occur either in a narrow belt which surrounds the Pacific Ocean or in a line which extends from Burma to the Alps in Europe. Some of the destruction is directly caused by the quake itself. An example of this is the collapse of buildings as a result of the quake itself. Other damage results from landslides or major fires which are initiated by the quake.
These are about a million quakes a year. Fortunately, however, not all of them are destructive. The intensity of an earthquake is measured on the Richter Scale, which goes from upward. The highest scale recorded to date is 8.9. Major damage generally occurs from quakes ranging upward from 6.0.
The actual cause of the quake itself is the breaking of rocks at or below the earth’s surface. This is produced by pressure which scientists believe
[单项选择]Every year television stations receive hundreds of complaints about, the loudness of advertisements. However, federal rules forbid the practice of making ads louder than the programming. In addition, television stations always operate at the highest sound level allowed for reasons of efficiency. According to one NBC executive, no difference exists in the peak sound level of ads and programming. Given this information, why do commercials sound so loud
The sensation of sound involves a variety of factors in addition to its peak level. Advertisers are skilful at creating the impression of loudness through their expert use of such factors. One major contributor to the perceived loudness of commercials is that much less variation in sound level occurs during a commercial. In regular programming the intensity of sound varies over a large range. However, sound levels in commercials tend to stay at or near peak levels.
Other "tricks of the trade" are also used. Because low-freq
A. does not exceed that of programs
B. is greater than that of programs
C. varies over a large range than that of programs
D. is less than that of programs
