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“笔石纲”的英语可以翻译为：Graptolithina，Graptozoa ...

“笔石”的拼音为：bǐ shí...

表明笔石详细构造的物质是利用氢氟酸从石灰岩中侵蚀出来.Material illustrating detailed structure of graptolites has been etched from limestone by means of hydrofluoric acid.从而为笔石反射率的正确测定和取值奠定了基础.These provide base for the correct measurement and val...