基本解释[机械工程]轻铅笔线英汉例句双语例句Using a ruler, mark a light line with your pencil down the left-hand edge, about 1-2cm in.用尺子在左边画一条直线，离边缘1-2厘米。light pencil line更多例句专业释义机械工程轻铅笔线