名词
中文翻译：Unknown
同义词：
['sign', 'indicator', 'beacon', "signal light例句：1. The police officer used his flashlight to signal the driver to slow down.（警察用他的手电筒向司机示意减速。）2. The ship's horn was a loud signal for all on board to gather.（船的号角是所有船上人员集合的信号。）3. The pilot used a flare to signal the approach of an airplane.（飞行员用信号弹来指示飞机接近。）"]
例句：
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1. The police officer used his flashlight to signal the driver to slow down.
警察用他的手电筒向司机示意减速。
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2. The ship's horn was a loud signal for all on board to gather.
船的号角是所有船上人员集合的信号。
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3. The pilot used a flare to signal the approach of an airplane.
飞行员用信号弹来指示飞机接近。