tail fold

例句：

1. 1.The dog's tail folds over as it runs.
   狗奔跑时尾巴会卷曲。
2. 2. The cat's tail folds neatly when it sits.
   猫坐下时尾巴整齐地卷起。
3. 3.The bird's tail folds up when it flaps its wings.
   鸟拍打翅膀时尾巴折叠起来。