题目

第三部分  阅读（共两节，满分40分） 阅读理解 （共15小题， 每小题2分，满分30分）       阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出 最佳选项，并在答题卡上将该项涂黑。 Two American scientists told the people in industrial nations（工业国） that they would be much healthier if they ate more of the same kind of foods eaten by humans living more than 10,000 years ago． The scientists say that the human body has changed very little since human first appeared on earth, but the way we live has changed 在一定条件下，对于密闭容器中进行的反应：N2 (g) + 3H2 (g)  2NH3 (g)，下列说法能充分说明该反应已经达到化学平衡状态的是 A．正、逆反应速率都等于零       B．N2、H2、NH3的浓度均不再变化 C．N2、H2、NH3在容器中共存     D．N2、H2、NH3的浓度相等