一个不透明的盒子中装有2个白球，5个红球和8个黄球，这些球除颜色外，没有任何其它区别，现从这个盒子中随机摸出一个球，摸到红球的概率为(      )

用方框中所给单词的适当形式填空，（每个单词限用一次）。

       Is it good to be in the middle? Sometimes, no, like when you’re in the middle seat on a long car ride. But sometimes, ____, like when you’re in the middle of a great movie. What will happen next? Middle school is ____ bit like that.

     Middle school is called middle school ____  it’s in the middle of your school years. Elementary school is ____ you. High school and possibly college still await(等待) you. Middle school often includes sixth, seventh, and eighth ____, but you might go to middle school earlier or later, depending on how it's done in your area.

    For a kid, going to middle school is often a big change:

       ·First, it often means moving to a new ____, which takes some time to adjust(调整) to.

      ·Second, it may mean taking a different bus, with different students.

      ·Third, the friends you ____ in elementary school may end up going to different middle schools.

    All that can make you ____ a bit scared on the first day of school.

    Other things that probably will be different are the teachers and the work. Have you heard that middle school teachers are really mean and the homework is really, really ____? Oh, dear. We've heard those, too, but usually they’re not ____. Yes, you'll like some teachers better than others, but middle schools are not special for teachers!

你会说解说词吗？观察下面图片，以下列任何一个人物的主要活动为例，说说唐代中外交流的发展情况？(注意：要回答出人物的活动、作用及其反映的当时对外关系特点。)