車床分類問(wèn)題

real_ynice

今天注冊(cè)個(gè)網(wǎng)站有個(gè)問(wèn)題要回答，看了之后難住了，不知道答案是什么，看看有沒(méi)有大俠能夠解答下。
Two very different types of lathes typically used to turn two types of materials...one natural, one manmade. What are they ?
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kobe愛(ài)學(xué)習(xí)

學(xué)習(xí)一下
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