都江堰、大运河、莫高窟、明长城、北京故宫都是（    ）

某校高二（6）班学生每周用于数学学习的时间x（单位：小时）与数学成绩y（单位：分）构成如下数据（15，79），（23，97），（16，64），（24，92），（12，58）．求得的回归直线方程为$\stackrel{\wedge }{y}$=2.5x+$\stackrel{\wedge }{a}$，则某同学每周学习20小时，估计数学成绩约为多少分？

阅读下面短文，在空白处填入一个适当的词，或填入括号中所给单词的正确形式。

    Malala Yousafzai, 19, is a Pakistani youth activist. She is the ____（young）person in the world ever to be named United Nations（U.N.）Messenger（信使）of Peace. The United Nations is ____ international organization, which is meant to encourage ____（country）to work together on different opinions without the use of war. Yousafzai has ____(glad) accepted the role of working for girls'education. Usually, a messenger ____(stay) in the position（职位）for three years. “If ____ want to see your future bright, you have to start working now and not wait ____ anyone else,” she said at the acceptance meeting in New York. In 2012, Yousafzai was nearly killed by the Taliban because she worked hard ____(get) the same education for young girls in Pakistan. But later her condition improved. ____ a brave girl! Since then Yousafzai ____(become) a symbol for peace and girls' right to receive an education.

西城区慈悲庵内建有陶然亭，清代翁方纲为陶然亭撰写对联，上联是“烟笼古寺无人到”，下联应是（   ）。