已知：2NO2（g）⇌N2O4（g）△H＜0．现将NO2和N2O4的混合气体通入恒温密闭容器中，反应体系中物质浓度随时间的变化关系如图所示．下列说法正确的是（ ）
A．a点表示反应处于平衡状态 B．25 min末，若增大压强，化学平衡常数增大 C．25 min末，若升高温度，化学平衡常数不变 D．10min内用N2O4表示的平均反应速率为0.02mol•L-1•min-1 |
答案：D
What can be concluded from the passage
A．Medical tests and education for Americans with diabetes are not covered by the present healthcare schemes.
B．If you are 20 years old or more, you are more likely to suffer from diabetes.
C．Family help is the more important and most effective in detecting and treating diabetes.
D．In the US, July 1 is a day of celebration for hospital staff, nurses and patients.
