One tree swallow was in the nest and the other on guard outside.

一只树燕子在窝里，另一只在外面站岗。

Get an old, wild-apple tree into the sanctuary for the bluebird, the kingbird, the tree swallow, and the chebec.

为青鸟、王霸鹟、树燕以及北美小霸翁鸟在保护区种植有年头的野苹果树。

But on the telephone wire sat a pair of tree swallows, their steel-blue coats and white shirt fronts glistening in the sunlight.

但电话线上坐着一对树燕子，钢蓝色外套和白色衬衫前襟在阳光下闪闪发光。

Just as he had hoped, the first bluebirds built in one of the smaller boxes, and a pair of tree swallows in the other.

如他所期，第一只蓝知更鸟的窝建在一个小盒子里，一双树燕住在另一个盒子里。