optimum design of bridge

例句：

1. 1. The optimumtemperature for growing crops is between 20°C and 30°C.
   农作物生长的最佳温度范围是20°C到30°C。
2. 2.The optimum level of education requiredto achieve this goal is a bachelor's degree.
   为了实现这一目标，所需的教育水平是学士学位。
3. 3. The optimumdesign of the bridge was achieved by usinga lightweight but strong material.
   这座桥梁的最优设计是通过使用轻质但坚固的材料实现的。