附加题（1）石墨晶体的层状结构，层内为平面正六边形结构（如图a），试回答下列问题：图中平均每个正六边形占有C原子数为____个、占有的碳碳键数为____个，碳原子数目与碳碳化学键数目之比为_______。

（2）2001年报道的硼和镁形成的化合物刷新了金属化合物超导温度的最高记录。如图b所示的是该化合物的晶体结构单元：镁原子间形成正六棱柱，且棱柱的上下底面还各有1个镁原子，6个硼原子位于棱柱内。则该化合物的化学式可表示为_______。

One afternoon, my son Adam asked me, "Are all people the same even if they are different in color " I thought for a minute, and then I said, "I’ll explain,（1）you can just wait until we make a quick stop at the grocery store. I have something （2） to show you. "At grocery store, we bought some apples-red, green and yellow ones. Back home, I told Adam, "It’s time to（3） your question." I put one apple of each type on the table. Then I looked at Adam, who had a （4） look on his face."People are like apples. They come in all different colors, shapes and sizes. On the（5）, some of the apples may not even look as the others. " As I was talking, Adam was（6）each one carefully. Then, I took each of the apples and peeled them, placing them back on the table, but （7） a different place."Okay, Adam, tell me which is which." He said, "I can’t tell. They all look same now." "Take a bite of （8）. See if that helps you decide which one is which. "He took（9） , and then a huge smile came cross his face. "People are just like apples! They are all different, but once you（10）the outside, they’re pretty much the same on the inside. "He totally got it. I didn’t need to say or do anything else.

第（10）空应选择（）

A. put away

B. get down

C. hand out

D. take off