root of the tail

例句：

1. 1. The dog's tail is a good indicator of its mood.
   狗的尾巴是它情绪的好指标。
2. 2. The scientist studied the root of the tail to understand how it works.
   科学家研究尾巴的根部以了解其工作原理。
3. 3. The researcher found that the root of the tail plays an important role in the animal's behavior.
   研究者发现尾巴的根部在动物行为中起着重要的作用。