"Coral reefs only make up about one tenth of one percent of the ocean floor."

VOA: standard.2010.05.26

You feel heavy and it reads more because the poor spring not only has to support you from falling through the floor, but also accelerate you counter to what gravity wants to do.

你感到自己变重以及读数增加,因为现在弹簧不仅要支撑你,不让你掉下来,还要抵消重力的作用让你加速

耶鲁公开课 - 基础物理课程节选

Pre-programmed cleaning cycles allow consumers to choose between floor-only cleaning or floor, wall and waterline cleaning, a necessary chore that many pool owners just don't want to do manually.

ENGADGET: Polaris' pool-cleaning robots get updated with added intelligence, four-wheel drive

There is, after all, only so much floor space in any given department store.

ECONOMIST: Retailing

That is because Social Security is a contributory program that only replaces a floor of wage income in retirement.

FORBES: Warren Buffett's Public Disservice On Taxation