We have no idea about  1 men first began to use salt. But we do know that it had been used in many different ways 2 the history.
For example, in many history books it is 3that people who lived three thousand years ago 4salted fish. Thousands of years ago in Egypt（埃及）, salt 5 keep the dead. It can keep the dead bodies6decay.（腐烂）
   In the eighteenth century, a person who stole salt was 7 to have broken the 8. if a person was caught stealing salt, he would be thrown into 9. Books also record that in England about ten thousand people were put into prison during that century10stealing salt! In the year 1553, if a man took 11than his share of salt, he would be thought to have broken the law and would be12 punished(惩罚).
   oSalt was very13 on the dinner table of a king. It was always put14 the king when he sat down to eat. Then important visitors sat near the salt15 less important visitors were given seats farther away from it.

下列与化学概念有关的说法正确的是（   ）

判断正误．

不是正数的数一定是负数．

Don’t feel sorry for disabled or________ them, just accept them.

定义在R上的偶函数f(x)满足：对任意的x₁，x₂∈0，＋∞)(x₁≠x₂)，有$\frac{f\left(x_2\right)-f\left(x_1\right)}{x_2-x_1}<0$，则(　 )