Can you hear This ？
When something creates a sound wave in a room or an auditorium （礼堂），listenershear the sound wave directly from the source. They also hear the reflections asthe sound bounces off the walls ， floor ，and ceiling . These are called the reflected wave or reverberant （反射的） sound ， which canbe heard even after the sound is no longer coming from the source .
The reverberation time of an auditorium is determined by the volumeor interior size of the auditorium .It is also determined by how well or howpoorly the walls ， ceiling， floor ， and contents of the room （including the people） absorb sound. There is no ideal reverberation time .The full-soundperformance of music such as Wagner operas or Mahler symphonies should have along reverberation time. The light ，rapid musicalpassages of Bach or Mozart need a reverberation time somewhere between .
Acoustic problems often are caused by poor auditorium design .Smooth， curved （弯曲的）reflecting surfaces create large reflections . Parallel （平行的）wallsreflect sound back and forth， creating a rapid ，repetitive pulsing（有节奏的跳动）effect. Large pillars （柱）and corners can cause acoustic shadows as the sound waves try topass around the object. Some of these problems can be solved by using absorbersand relectors to change the reverberation time of a room .For example ， hanginglarge reflectors ， called clouds ，over the performers will allow some sound frequencies toreflect and others to pass to achieve a pleasing mixture of sound.
1.This Passage is mainly about
A sound waves and their acoustic effect
B the types of music orchestras play
C walls of an auditorium
D the design ofan auditorium
2.Wagner operas and Mahler symphonies sound fuller in an auditoriumwith
A a short reverberation time
B a long reverberation time
C an intermediate reverberation time
D noreverberation time
【解析】文章第二段说Thefull-sound performance of music such as Wagner operas or Mahler symphoniesshould have a long reverberation time，由此可知选B。
3.This passage suggests that a good auditorium should
A achieve a pleasing mixture of sound
B get rid of all reflections
C not have absorbers.
D have smooth surfaces
【解析】通过文章最后一句For example, hanging large reflectors, called clouds, over theperformers will allow some sound frequencies to reflect and others to pass toachieve a pleasing mixture of sound可知应选A。
4.Large pillars and corners may
A make sound rich and full
B be cures for sound problems
C be sources of sound problems
D function as well as clouds
【解析】文章最后一段说Large pillars and corners can cause acoustic shadows as the soundwaves try to pass around the object，可知答案选C。
5.The word “acoustic ”in the last paragraph has something to do with
D noise SmartWindow