Distortion Phenomenon Analysis of 3m Ruler Used in the Test of Hot Surface Smooth
3m直尺用于热铺层平整度检测时的'热变形现象分析
The teacher came in and a ruler was in his hand.
老师走进教室，手里拿着一把直尺。
Take out a ruler draw a line.
拿出直尺，画条线；
Proportional servo valve, grid ruler and CNC machine tool
伺服比例阀、光栅直尺与数控机床
At breast height, measure the trunk diameter by a ruler.
在胸部高度的位置，用一把直尺量度干径。