The air gets thinner ad you go higher.本句中的ad

-应该是as吧,“随着,当...时”.随着你升的更高,空气变得更稀薄.
d和s紧挨着,一般是打错了.
再问： 我在网上搜索了好多，没有写AS的啊，全部都是ad的
再答： ad明显讲不通。网上文章都是复制粘贴的， 错了一个， 另一个也错了。 我看到了另一篇文章。 If someone ask you, “What colour is the sky?”I think you will answer “Blue”.I’m afraid that you will be wrong. The sky has no colour. It looks blue because we are looking at blue sunlight. The sunlight is shining on little bits of dust (灰尘) in the air. Is the sky full of air? I’m sure that you have asked this question, too. We know that there is air all around the world, but we couldn’t fly very high 【because as we go higher, the air gets thinner】. If we go far enough away from the earth, we find there is no air. Maybe we can answer some questions now. What is the sky? Where is it? It is all round the world. The sky is space (宇宙空间). In space there is nothing, but only the sun, the moon, and all the stars.