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科学素养与生活应用·英语30篇(9)

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Why Elevators Stop at the Right Floor Every Time

Why Elevators Stop at the Right Floor Every Time

电梯为何每次都能准确停靠在目标楼层

  1. Inside each elevator shaft are markers for every floor level.
  2. Sensors on the elevator car read these markers as it moves up or down.
  3. A computer matches the marker signal with the button you pressed.
  4. Motors slow the car smoothly before reaching the exact spot.
  5. Brakes hold it steady so the doors line up perfectly with the floor.
  6. Precision engineering makes tall buildings easy and safe to use.
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