According to Para. 5, we can infer that
A. the local people have suffered a lot because of a new project.
B. the rich people have helped the local people set up a special business.
C. by leaving their homes, the local people can get much benefit.
D. to obtain profits, a thoughtless government made the local people suffer great loss.
查看答案
What is the aim of Cultural Survival, Inc. and its sist'er organizations？
A. To teach people how to communicate with the outside world.
B. To study the cultures of the modern world and some other societies.
C. To help small and isolated tribes adapt to the modern world.
D. To separate some societies from the modern world.
Sound is audible to human beings only if the frequency is
A. fewer than about 20 vibrations per second.
B. more than about 20,000 vibrations per second.
C. about in a range of 20 and 20,000 vibrations per second.
D. 120 vibrations per second.
Decibel is
A. the unit for measuring the4ntensity of sound.
B. the pressure of radiating waves.
C. the frequency of radiating waves.
D. the speed of sound.
Which of the following can serve as the best title of this passage？
A. The Prefix Mach
B. The Speed of Sound
C. The Frequency of Sound
D. The Intensity of Sound
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