三是不稳定的空气状态。这是重要的局地热力条件。沙尘暴多发生于午后傍晚说明了局地热力条件的重要性。

Three is not stable air condition. This is an important local thermal conditions. Sandstorm occurs more often in the afternoon that incorporates the evening the importance of thermal condition.

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鸭式无尾翼布局具有高度机动性和优越的超音速性能，但亦具有先天空气动力上之不稳定性。

The tailless delta-canard configuration is inherently aerodynamically unstable, which provides a high level of agility, particularly at supersonic speeds.

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原因如下：当与(空气中的)氧气，(烹饪时的)温度接触或者接受光照时，某些蛋白质将变得不稳定。

Here's why: certain nutrients are unstable when exposed to oxygen (from the air), heat (from cooking) and light.

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