Red is widely used to indicate danger (high voltage signs, traffic lights).

红色广泛用于指示危险(高压电警示、交通灯)。

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Switch-Position Pilot Lights: Indicate source to which load is connected.

开关位置指示灯：显示负荷连接至哪一种源。

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As a staff member or other person enters, the sink lights up in red to indicate that hands should be washed.

当医院人员或其他人员进入的时候，洗手台就会亮起红灯，表示需要洗手。

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