他随身携带了无线电设备，以便在紧急情况下呼叫经过这里的飞行员，但最终发现设备根本不起做用。

He carried a radio so he could call commercial airline pilots to relay messages in case of emergency, but he discovered that it wasn't working.

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动态心电图这是一种可随身携带的心电图，可以在你正常生活时连续记录下几天内心脏的电活动。

Holter monitor. This portable ECG device can be worn for a day or more to record your heart's activity as you go about your routine.

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