how they got on with each other他们之间相处又是如何改变进化历程的

get on with取得进展； 与 ... 友好相处； 继续做

Do you get on with your parents?

你和父母合得来吗?

To find the answer, we need to go back four million years想解开这一谜团就要回到400万年以前

go back回去

I may be going back in the fall.

我可能在秋天回去。

He is now fit enough to go back to work.

他现在身体健康，可以回去工作了。

surviving on a diet of raw fruit and vegetables.单靠生鲜蔬果为生

survive on靠 ... 活下来； 靠 ... 生存

These players have to survive on their wiles.

这些运动员得靠诡计才能不被淘汰。

They can survive on very little money.

他们用很少的钱就可以生存。