What "friends" did the author visit in the mountains?

The author visited some friends in nature in the mountains, such as ancient bridges, birds, dewdrops, trees, mountain springs, streams, waterfalls, cliffs, white clouds, larks and fallen leaves.

The theme of the text is "visiting friends in the mountains", which is not only the basis of the whole text, but also the unique and distinctive expression method of association and imagination to create a situation. It is the crowning touch of the article, and it can also arouse readers' speculation about which "friends" the author visited in the mountains. Thereby stimulating readers' interest in reading.