Breakfast is very important. It is one of the most important1of the day. To keep healthy, everyone should2a good breakfast.3the right food is necessary for good health. We may have eggs, bread, milk and so on,4breakfast. Many students go to school without breakfast5they get up late or their parents don't cook for them. It's6for their health.7breakfast children may not grow fast and may not study and play very well at school. They may8. And when they're ill, they will9a long time in recovering (恢复). I think everyone should have some good10habits. It is necessary.

若不论k为何值，直线y=k(x-2)+b与曲线x²-y²=1总有公共点，则b的取值范围是（　　）

把6molA和5molB两气体通入容积为4L的密闭容器中，一定条件下反应：3A（气）+B（气）2C（气）+xD（气）；△H＜0，5min达平衡，此时生成2molC，测得D的平均反应速率为0.1mol·(L·min)^-1。下列说法中正确的是（      ）