If the plane is downed in the ocean, the black box sends out a signal that can travel up to three kilometers away.

如果飞机坠入大海，黑匣子会发送信号，三公里外都能追踪到该信号。

youdao

The municipal central meteorological observatory of Shanghai said the typhoon will not grow weakened until Sunday morning and already sent out a black warning signal Saturday.

上海市中心气象观测站说到周日早上前台风的势头不会减弱，并已在周六颁布了黑色台风警告。

youdao

In the firstone. black clouds of exhaust fume are emitted from a highchimney. to thes trend one. a signal tower stands instead ofthe ugly chimney. sending out invisible harmful radiation.

第二幅图中一座信号塔取代了丑陋的烟囱。放射出无形的有害辐射。

youdao

That rather obvious problem accounted for 185 of the cases, with damage to the unit by the offender, problems with the black box in the offender's home, and a weak signal rounding out the technical difficulties.

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