half of thread angle

例句：

1. 1.The carpenter measured the length of the wooden beam with a tape measure and marked the half of thread angle on the wall.
   木匠用卷尺测量木梁的长度，并在墙上标记了线角度的一半。
2. 2. When cutting a square, you need to mark the half of thread angle on one side and use itas a guide for cutting the other sides.
   当切割一个正方形时，你需要在一边标记线角度的一半，并用它作为切割其他两边的指南。
3. 3. The engineer used the half of thread angle to calculate the angle between two lines in the drawing.
   工程师使用线角度的一半来计算图纸上两条线之间的夹角。