像可切割或刮刨的锋利石片这些原始工具，可能在早在一百万年前就已存在。
Crude tools, such as sharp stones for cutting or scraping , may have existed as long as a million years ago.
它就像一把地质锉刀一样通过刮、刨等作用来磨损冰川流过的表面。
It ACTS as a geologic rasp, scratching, gouging and generally abrading the surfaces over which the glacier rides.
圆环链适用于煤矿刮板输送机、刨煤机、 滚筒采煤机及其它机械牵引链等。
Ring chain is applicable to coal mine scraper conveyor, plough, drum shearer and other mechanical traction chain, etc.
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