constant in curriculum

例句：

1. 1. The sun is constant in itswarmth and light.
   太阳以其温暖和光芒而恒定不变。
2. 2. The river flows constantlythrough the valley.
   这条河流不断地流经山谷。
3. 3. The weather is constant throughout the year.
   全年天气都保持不变。