VOA慢速英语:Knife Cuts on Mastodon Bone Reveal Earlier Humans

短语讲解：

1. Researchers from several universities worked together and published their findings in the journal Science Advances.

work together 合作; 同…在同一处工作; 同事
例句：We work together in harness for the president.
我们都是总统的马前卒。

2. Researchers used carbon dating -- a scientific method -- to find out the age of the objects.

find out 发现; 使发作
例句：I'll find out the address,and ring you back.
我找到地址后再与你通电话。

3. It had been cut. Mastodons were large ancient animals that once lived on Earth, but died off thousands of years ago.

die off 相继死去，先后死去
例句：His few remaining kinsfolk die off
他仅有的几位亲属相继去世了。

4. In other words, those marks on the mastodon bone?

in other words 换句话说; 就是说
例句：In other words, menus provide a pedagogic vector.
换句话说，菜单是一条学习的途径。