读城市地域结构的理论模式示意图，完成下列问题。

    All of us know that breakfast is very ____ 'nesəsərɪ to us. It is____of the most important meals of the day. To keep ____ (health), everyone should have a good breakfast.____ (eat)the right food is good for our health. We can have eggs, bread, milk and other food ____ breakfast.

    Many students go to school without breakfast.____  bɪ'kɒz they get up late or their parents don't cook for them. It's ____ for their health.

    Without breakfast children may not____grəʊfast and may not study and play very well at school. They may be easier to get____(ill). And when they're ill, it will____(take) them a long time to recover（恢复）. I think everyone should have some good eating habits.

已知函数$f\left(x\right)=\left\{\begin{array}{c}-x^2,x\ge 0\\ x^2,x<0\end{array}\right.$若$f\left(a-2\right)+f\left(a\right)>0$，则实数a的取值范围是（  ）