extension meter

例句：

1. 1.The engineer used an extension meter to measure the distance between two points.
   工程师使用延伸计测量两点之间的距离。
2. 2. The doctor recommended using an extension meter to check the patient's blood pressure.
   医生建议使用延伸计来检查患者的血压。
3. 3. The scientist used an extension meter to measure the thickness of the material.
   科学家使用延伸计来测量材料的厚度。