The hot-air balloon doesn't depend on power, but float by means of wind. Because the wind direction and speed vary with the height, the driver can choose the proper height as the flight required.

但是，由于风在不同的高度有不同的方向和速度，驾驶员可以根据飞行需要的方向选择适当的高度。

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At the end of the lease term, the driver owes a balloon payment.

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