The oldest hafted spears date from about 500,000 years ago, but they're more common starting around 300,000 years ago.

最古老的斧状矛可以追溯到大约50万年前，但在30万年前更为常见。

For example, one thing they study is hafted weapons, spears made by mounting a sharpened stone or bone onto a stick.

例如，他们研究的一件物品是用斧头武器——把锋利的石头或骨头装在棍子上制成的长矛。