根据句子意思及所给的词首字母或汉语提示，完成下列单词。（5分）

小题1:Some people                (浪费) food while others don’t have enough food to eat.

小题2:Linlin is good at English, but I’m w               in it.

小题3: In the past, few children had the chance to receive a good              （教育）.

小题4:—Have you ever been a             _?

—No, I have never been to any foreign country.

小题5:You can’t learn English well u               you work hard.

将点燃的镁条伸入CO₂中，镁条继续燃烧，生成一种黑色固体单质和一种白色粉末．请写出该反应的化学方程式______，该反应是______（填基本反应类型）．根据以上所述，你对燃烧或灭火有什么新认识？请写一点：______．