parallelogram of forces

例句：

1. 1. The architect designed a parallelogram for the roof of the building.
   建筑师为大楼的屋顶设计了一个平行四边形。
2. 2. The teacher explained how to draw a parallelogram using a ruler.
   老师解释了如何使用直尺来画一个平行四边形。
3. 3. The student drew a parallelogram on the whiteboard.
   学生在白板上画了一个平行四边形。