light pen unit

例句：

1. 1. The new light pen unit is more accurate than the old one.
   新的光笔单元比旧的更精确。
2. 2. The teacher used a light pen unit to demonstrate the concept.
   老师使用光笔单元来演示这个概念。
3. 3. The student was able to use the light pen unit to solve the problem on his own.
   学生能够自己使用光笔单元解决这个问题。