氧化铝是红宝石、蓝宝石的主要成份，它由铝离子和氧离子构成．

氧化铝的化学式为____；3个铝离子的化学符号是____．

氧离子的结构示意图为 ，一个氧离子中有____个质子．

阅读下面的短文，根据短文内容完成句子。每空词数不限。

    This is a song millions of Americans will hear this New Year's Eve. It is called “Auld Lang Syne(《友谊地久天长》)”. It is the traditional music played during the New Year's celebration. Auld Lang Syne is an old Scottish poem. It tells about the need to remember old friends.

    The words “auld lang syne” means “old long since”. No one knows who wrote the poem first. However, a version (译本) by Scottish poet Robert Burns was published in 1796. The words and music we know today first appeared in a songbook three years later.

    The song is played in the United States mainly on New Year's Eve. The version you are hearing today is by the Washington Saxophone Quartet. As we end our program with “Auld Lang Syne”, I would like to wish all of our radio friends a very Happy New Year! This is Buddy Thomas.

如图所示，质量为5kg的物体A在大小为5N的拉力F作用下做匀速直线运动．己知滑轮组机械效率为80%，物体运动的速度为1m/s．下列选项中正确的是（   ）