《论语》中有这样一段话：子贡问孔子怎样才能成为一个真正的“士”，孔子说“行已有耻”是第一要求，这里的行已有耻，就是对自己的不良行为要有羞耻之心。在孔子的心目中，知耻是第一位。由此我们可以知道，要有自尊，就应该（    ）

用液态二氧化碳灭火器扑灭图书失火的原理是____ 

A．隔绝空气      B．降低图书的着火点      C．清除可燃物      D．____ 

（Ⅰ）若 $\overrightarrow{m}$ ⊥ $\overrightarrow{n}$ 且0＜x＜π，试求x的值；

（Ⅱ）设f（x）= $\overrightarrow{m}$ • $\overrightarrow{n}$ ，试求f（x）的对称轴方程和对称中心．

短文改错

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（﹨）划掉。

修改：在错的词下面划一横线，并在该词下面写出改正后的词。

注意：1．每处错误及其修改均仅限一词；2．只允许修改10处，多者（从第11处起）不计分。

    I am writing to express my interest in your recently advertised positions as a secretary of English. Here I would like to introduce me briefly. I am a 25-year-old young man graduated from the Foreign Languages Department of Jilin University. I have been a English guide for two years after graduation. As a result, my oral English is pretty well. I think the job is suitable for me. I had much confidence of myself. If I am given to the job, I promise I will do my best to do it well. I'd like to meet you at your convenient to discuss the possibility of working in your company. An early reply to my application will be high appreciated.

将希波战争、亚历山大东征、罗马帝国的扩张和十字军东侵纳入同一个专题进行研究，专题名称最恰当的是(   )