但在最近一次在巴西帕拉州雨林边界上空的侦察飞行中，空气中竟然连片缕烟丝都没有。

But on a recent surveillance flight over the forest frontier in Brazil's state of para, there was hardly a wisp of smoke in the sky.

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遥控飞机，有的只有飞机模型那么大，有的则有美国的“捕食者”无人机和“全球鹰”无人侦察机那么大，例行地监测阳光穿过云层的情况，以及在飓风上方进行飞行。

Remotely operated planes, some the size of model airplanes and some the size of military Predators and Hawks, routinely monitor sunlight passing through clouds and fly over hurricanes.

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“扫描鹰”的最大飞行高度超过4880米(16000英尺)，可以提供低空侦察能力。

Capable of flying above 16, 000 feet, the unmanned aircraft provides low-altitude reconnaissance.

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