Analogous to a snow avalanche on a steep mountain slope, an incoming light pulse initially frees just a few charge carriers which in turn free others until the original signal is amplified many times.
像陡峭山坡上的雪崩一样，一束入射光的脉冲最初仅仅释放少数的电荷载子(charge carrier)，这些电荷载子再轮流释放其他的载子，直到原始信号被放大很多次。
One girl tried to call her mum with her mobile phone but there was no signal in the mountain area.
一个女孩试图打电话给她妈妈和她的手机，但在山区没有信号。
Yes, it's a small mountain village. My cellphone couldn't receive signal there.
是的，是一个小山村。我的手机在那里收不到信号。
Tom: 112. People believe that the number is useful when they are in danger, such as in the valley or in the mountain area. Even through the signal is very bad, the police could know where you are.
人们相信这个电话号码在他们处于危机的是有用的，比如说在山谷里，或者是在山区里，即使信号非常的差，警察还是能知道我们在哪里。
Nobody knew what to do. One girl tried to call her mum with her mobile phone but there was no signal in the mountain area.
没有人知道该怎么做，有个女孩试图给妈妈打电话，但是山区没有信号。
One girl tried to call her mum with her mobile phone but there was no signal in the mountain area.
一个女孩试图叫她妈妈与她的移动电话，但山区没有信号。
They know This is a signal, then is riding the camel, climbs over the mountain, the traversing desert and the plain, along star direction, Goes toward the Bethlehem direction.
他们知道这是一个信号，便骑着骆驼，爬过高山，穿越沙漠和平原，沿着星星的指引，往Bethlehem方向而去。
They know This is a signal, then is riding the camel, climbs over the mountain, the traversing desert and the plain, along star direction, Goes toward the Bethlehem direction.
他们知道这是一个信号，便骑着骆驼，爬过高山，穿越沙漠和平原，沿着星星的指引，往Bethlehem方向而去。
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