curvature of the metric

例句：

1. 1. The metric system is widely used in many countries.
   公制系统在许多国家广泛使用。
2. 2. The new ruler is 30 centimeters long, which is a metric measurement.
   新尺子长30厘米，这是一个公制测量。
3. 3. The metric conversion table is essential for understanding the value of different currencies.
   公制换算表对于理解不同货币的价值至关重要。