Life is based on the universal principle of the specific interaction of molecules with each other.Interacting molecules interact as pairs,one of which is called the ligand and the other the receptor.

• 生命是建立在分子之间具体互相影响的普遍原理之上的，相互影响的分子成双的影响着彼此，一个称为向心体另一个称为接收体。