大约10000-12000年前，原始犬类远居于人类居住地，清除残羹、粪便和其他的人类垃圾。

Proto-dogs scavenged around the outskirts of human settlements about 10, 000 to 12, 000 years ago, removing food scraps, feces, and other human waste.

youdao

我听到了后也很高兴，我清除完垃圾后就回家了，我当时觉得我是世界上最快乐的人。

I also felt happy when I heard this. I cleaned the dirty things at once and came back home. It seemed I was at the top of the world.

youdao