英语语法分析

The researchers say they have also done the first nuclear genetic analysis of the American mastodon.

研究人员说他们已经完成了首个美洲乳齿象的细胞核遗传学分析。

Scientists have now accurately carbon-dated the sharp tip that itself carved from mastodon bone.

如今，利用放射性碳素测定年代法，科学家已确定这一用乳齿象牙雕刻而成的长矛尖端的精确年代。

The rib containing the spear point was part of a collection of mastodon remains unearthed in the late 1970s.

这一含有长矛尖的肋骨来自一批20世纪70年代后期采集出来的乳齿象遗骸。