是个病句,应分成2句.
A dog or a cat can teach us a lot about human nature.They are a lot more like us than some might think.
A dog or a cat (主语)can teach (谓语)us 宾语a lot 双宾语about human nature(宾补).一只狗或者猫可以告诉我们很多关于人类的自然属性.
They 主语 are系动词 a lot more like us 表语 than some might think 比较状语从句.它们比某些人可能想象的更像我们.