2014 年 12 月 12 日，历时 11 年建设的            中线一期工程正式投入使用，标志着东、中线一期工程建设目标全面实现。（    ）

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.

抛物线y＝－(x＋2)²－3的顶点坐标是（    ）．