Swallows migrate south in winter.

燕子在冬天迁徙到南方。

There were swallows in the cloudless blue sky.

燕子在无云的蓝天上飞翔。

Are you satisfied with flying swallows?

你对飞翔的燕子感到满意吗?

Swallows fly about, carefree and at liberty.

燕子自由自在地飞翔。

Swallows carry bits of earth in their bills to build nests.

燕子衔泥筑窠。