Birds
Birds don't fly high up in the sky. The air is too thin.
It is hard for birds to breathe in thin air. Thin air doesn't hold them up.
Birds fly near the ground so that they can see where they are. The birds look for places they know. Then they do not get lost. Some birds fly so low over the ocean that the waves often hide them. Many birds fly a long distance in the spring and autumn.
Birds
点击下载文档文档为doc格式
声明：除非特别标注，否则均为本站原创文章，转载时请以链接形式注明文章出处。如若本站内容侵犯了原著者的合法权益，可联系本站删除。
上一篇
已经是第一篇
下一篇