1. Humans are vertebrates.
人类是脊椎动物。
2. Fish are a type of vertebrate.
鱼类是脊椎动物的一种。
3. Birds have a spine, so they are vertebrates.
鸟类有脊椎,因此属于脊椎动物。
4. Reptiles like snakes and crocodiles are vertebrates.
爬行动物如蛇和鳄鱼都是脊椎动物。
5. All mammals have a spine.
哺乳动物都有脊椎。