Renaissance craftsmen, moreover, would have faced severe technical challenges in silvering and sealing a concave mirror, which required the application of hot tar and pitch on the outside of the glass.是什么意思_Renaissance craftsmen, moreover, would have faced severe technical challenges in silvering and sealing a concave mirror, which required the application of hot tar and pitch on the outside of the glass.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句