America's flintknappers produce over a million new arrow and spear heads every year.

美国的燧石工每年生产超过100万支新箭头和矛头。

They were master of flintknappers meticulously chipping and sharpening pieces of flint to make spears and cutting tools.

他们擅长用打火石精细雕刻，用尖利的碎石片制作长矛以及削制工具。