What office furniture do they need？
A. filing cabinets
B. desks
C. executive chairs
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From the passage we know______.
A. fire made human beings free from bacterial and parasitic infestation
B. fire enabled human beings to deal with immediate emergencies more efficiently
C. fire made some animals frightened
D. fire helped human beings change their eating habits completely
What discount is offered？
A. 8%
B. 10%
C. 12%
Which of the following statements is NOT true according to the passage？
A. In the past, people sometimes plugged their ears to fight against the offending noise.
B. An active noise-cancellation system follows the principle of a wave being flattened by meeting its exact opposite.
C. The first active noise-cancellation system was made in the 1930s.
D. Active noise-cancellation systems are now available on the market.
According to the passage, an active noise-cancellation system______.
A. contains noise rather than negates it
B. eliminates noise rather than muffles it
C. deflects noise rather than baffles it
D. holds noise back rather than stifles it
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