这只鸟在树上筑了一个巢。

The burd built a nest in the tree.

那只鸟在树上筑了一个巢。

The bird built a nid in the tree.

这只鸟在树上筑了一个窝。

The bird built a nide in the tree.

鸟在树上筑巢。

The bird builds its nest in the tree.

鸟在树上唱歌。

The niao is singing in the tree.

我看见一些鸟在树上方飞。（在树上方飞，鸟与树不接触）

I can see some birds fly over the tree.