physical pair

例句：

1. 1.The physics professor explained the principles of gravity to us.
   物理学教授向我们解释了万有引力的原理。
2. 2. The scientist conducted experiments to test the theory of relativity.
   科学家进行了实验来检验相对论的理论。
3. 3.The physical properties of gold are used in jewelry making.
   黄金的物理性质被用于制作珠宝。