translation.en: He argued -- and it's now a fairly common theory -- that if we found behavior patterns similar or the same in our closest living relatives, the great apes, and humans today, then maybe those behaviors were present in the ape-like, human-like ancestor some seven million years ago.
translation.zh: 他辨称 如果我们发现当代人类在行为模式上与 和其最相近的物种巨猿相似或者相同 那么或许这些行为在大概七百万年前 在似猿似人的祖先身上存在过