京燕

例句：

1. 1. The swallows are flying south for the winter.
   燕子们正在向南飞去过冬。
2. 2. She spent a lot of time watching the swallows in her garden.
   她花了很多时间在她的花园里观察燕子。
3. 3.The swallows were singing their mournful songs as they flew overhead.
   燕子们在飞过时唱着悲伤的歌曲。