这是比较难一点的as引导定语从句,as在里面充当了成分（as译为正如.）,这里,as就代替了the weather turned...这句话的内容.这是一个比较固定的结构,as...正如.再如：As is known to us,China is has a large populati...咋又是比较难的呢，不过这道题明白了 谢谢啊。As you know, English isn't very simple, is it? 哈哈哈，这句懂了吧。