Feedback loop — a closed path that connects an action to effect on the surrounding conditions which, in turn, can influence further action.

反馈循环——在一个循环条件下连接行为和结果的封闭回路，依次的，能影响更多行为。

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Double loop high speed vacuum suction system, spread to the surrounding air by the central.

双回路高速真空吸气系统，由中央向四周扩散吸气。

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It also includes the construction of highways and a continuous loop road surrounding the Olympic park to provide initial construction access and give vehicles venue access during the Games.

BBC: 2012 Olympic master plan revealed