向大家介绍这是我的老师，应该是：（   ）

如图，在一棵树的10米高B处有两只猴子，其中一只爬下树走向离树20米的池塘C，而另一只爬到树顶D后直扑池塘C，结果两只猴子经过的距离相等，问这棵树有多高？

我们共产党人是彻底的唯物主义者，_______落后和不足是客观存在的，我们_______不能采取极端的态度否认它，躲避它，_______要采取积极的态度。

    齐湣王既灭宋而骄，乃南侵楚，西侵三晋（赵、魏、韩国），欲并（吞并）二周，为天子。狐咺（齐臣）正议（义正辞严地劝谏），斫（斩首）之檀衢。陈举直言，杀之东闾。诸侯害（以为祸害）齐王之骄暴，皆争合谋与燕伐齐。

    三十一年，燕王悉起兵，以乐毅为上将军。秦尉（都尉，秦的中级武官）斯离（尉名）帅师与三晋之师会之。赵王以相国印授乐毅。乐毅并将秦、魏、韩、赵之兵以伐齐。齐湣王悉国中之众以拒（抵御）之，战于济西，齐师大败。

（节选自《资治通鉴》）

    A bus arrived and an old woman got on it slowly. She wore no shoes.

    A little boy pointed at (指) the old woman and said to his mother, “Look, Mum. She isn't wearing shoes.” “Don't point at others, Tom. It's rude,” the mother said and then looked out of the window.

    “She must have children,” said a woman in a fur coat. “Her children should buy shoes for her.”

    “People should learn to save money,” said a well-dressed man. “If she saved money when she was young, she wouldn't be so poor now.”

    Then all the passengers (乘客) on the bus stopped talking.

    At the next stop, a young man got on the bus. He was listening to music. When he saw the old woman, he stopped moving. He carried his eyes from her feet to his own. He was wearing his expensive new trainers. He saved money for months to buy them. Unexpectedly, the young man took off his trainers and socks. He stood before the old woman. “Madam,” he said, “I see you have no shoes. Well, I have.” Carefully and gently, he put his socks and fine trainers on the old woman's feet.

    Just then the bus arrived at the next stop. The young man got off the bus and walked away, wearing no shoes in the snow.

    “Who is he?” one asked. “He must be an angel (天使),” said another. But the honest (诚实的) little boy said, “No. He was only a man.”