已知二次函数y=2x²﹣4mx+m²+2m（m是常数）．

（1）求该函数图象的顶点C的坐标（用含m的代数式表示）；

（2）当m为何值时，函数图象的顶点C在二、四象限的角平分线上？

从2004名学生中抽取50名组成参观团，若采用下面的方法选取，先用简单随机抽样从2 004人中剔除4人，剩下的2 000人再按系统抽样的方法进行，则每人入选的概率是(　　)

根据句意或中英文提示写出所缺单词。
1. Water covers about three quarters of the earth's ____ .(表面)
2. ____ (though) he is very clever, he doesn’t work hard at his lessons.
3. Are you ____  (sure) Mr Wang will come to our meeting?
4. ____  with life on Earth, life on Mars will be better in many ways.(比较)
5. The Great Wall is one of the ____  (unusual things that fill people with surprise) in the world.