A同学学习化学后知道，镁在氧气中燃烧会生成白色的氧化镁固体．但他在空气中点燃镁条时，却发现在生成的白色固体中还夹杂着少量的淡黄色固体．

提出问题为什么会生成淡黄色固体？

查阅资料该同学查阅资料，记录了右

表中几种物质的颜色：

（1）其他同学认为不必查阅氯化镁的颜色，理由是____ ；

（2）提出猜想分析资料，A同学认为淡黄色固体可能是由镁与空气中的____ 反应生成的；

（3）实验探究该同学设计实验证实了自己的猜想，他的方案可能是　将点燃的镁条伸人充满氮气的集气瓶中，观察是否生成淡黄色的固体　；

（4）实验结论根据该同学的实验结果，写出镁条在空气中燃烧时发生的两个反应的化学方程式：____ 、____ 　；

（5）反思与评价通过上述实验，你对燃烧有什么新的认识？____ ．

某校七年级学生小强制作了人的口腔上皮细胞、洋葱鳞片叶表皮细胞临时装片，在显微镜下看到的情况如图所示，据图回答：

    This is a meaningful and impressive story. A man came to the USA. After settling down at ____island, he went into a cafeteria to get something ____ (eat). He sat down at an empty table ____ (silent) and waited for someone to take his order, ____ nobody did. Finally, a woman with a plate full of food ____ (sit) opposite him and informed him ____ the cafeteria worked. “Start out at that end,” she said. “Just go along the line and pick out what you want. At the other end, they'll tell you how much you have to pay.”

    “I soon learned how everything worked in the USA,” the man told a ____ (rely) friend. He said, “Life's a cafeteria here. You can get anything as long as you are ____ (will) to pay the price.”

    You can even get success, but you'll never get it if you wait for someone to bring it to you. You have to get up and get it ____ (you). You can't change the things that you can't avoid or prevent. The only thing you can do is control your attitude. Once you reach that point in life, ____ (achieve) won't be too far away.