19. We can understand from the passage that high decibel levels of sound ... A) result in bodily pain and upset the eyesight B) can only be resisted by means of earplugs
C) are only harmful when they are continuous D) deteriorate the nervous system permanently
20. The acoustic systems developed by SARA ... A) use high-intensity sound generators and are combustion driver.
B) did not meet the requirements of the US military.
C) do not, unlike other similar systems, cause any permanent damage whatsoever.
D) use sound levels which range from 120 to 140 decibels.
21. It's inferred in the passage that the new acoustic systems developed for the US military ... A) can cause permanent damage to the eye.
B) were primarily designed for use in wartime.
C) were primarily designed to break up crowds.
D) sometimes produce high-intensity vibrations that cause widespread damage to buildings.
22. According to the passage if the level of sound exceeds 140 decibels ... A) the sound produced is something between a siren and a whistle. B) there will be pain in all parts of the body.
C) then the crowds are readily dispersed. D) earplugs are required for protection.
In meeting, their responsibilities pet owners need to consider providing an enriching environment to reduce unwanted behaviour, e.g. excessive barking. A house that overlooks areas of activity is ideal for pets because it increases the amount of stimulation that can be received from the property, e.g. dwellings that overlook a park or are near a busy street. This is one way to alleviate boredom and the negative behaviours that sometimes results. Preferably a dog should have access to some outdoor space. Open space is not essential for a pet provided an enriching environment is maintained indoor, e.g. a bay window or internal fernery. Ideally dogs should have access to all areas of open space on a property. On the whole a dog’s behaviour is likely to be better if he or she can see the street. Although the dog may bark at passers-by in the street, there will be less likelihood of excessive barking that might arise from through boredom. Cats are not as easily restrained as dogs as they are more controlled and have quite different notions of territoriality. Mostly this does not create a problem, although difficulties may arise in environmentally sensitive areas where cats may prey on wildlife. It is recommended that cats be confined to the house at night for their own protection.