balance arc

例句：

1. 2.
   天平的
2. 1. The scales on the scale are balanced.
   秤上的指针是平衡的。
3. 2.The two teams are neck and neck in the competition.
   两队在比赛中势均力敌。
4. 3. The teacher balanced the class by assigning different tasks to each student.
   老师通过分配不同的任务给每个学生来平衡班级。