提取下面一段话的主要信息，写出四个关键词。

今天中国独特而强烈的爱国主义热情，直接源于“鸦片战争”以来的民族生存危机。在今天开放时代，中国与世界的关系发生了巨大变化，中国不但摆脱了民族生存危机，而且成为全球化竞争中的最大受益者之一。中国离不开世界，世界也离不开中国。这时的爱国主义应当注入新的因子和意识。它不再应当仅是一种内聚型的强烈感情，不应当是封闭的、种族的、排外的，而应当具有理性、深沉的意识，即开放的世界观、积极的进取心、普世的价值观念。

下列化学用语表示2个氢原子的是 （   ）

在图所示的光现象中，属于光的反射现象的是（　　）

根据短文内容，选择正确最佳答案。
American Classroom Rules
1. If the teacher asks a question, you should give an answer. If you do not understand the question, you should put up your hand and ask the teacher to repeat the question. If you don't know the answer, it's all right to tell the teacher that you don't know. Then he or she knows what you need to learn.
2. There is no excuse for not doing your homework. If you can not go to school, you should call your teacher or your classmate and ask for the homework. It is your responsibility（责任）to find out what homework you have missed. It is not the teacher's job to remind you of missed homework.
3. You must not be absent(缺席) on a test day. If you are badly ill, call and let the teacher know you will not be there for the test. If your teacher allows you to take a makeup, you should take the test within one or two days after you return to class. Bad illness is the only reason for missing a test.
4. Be on time! It's not polite to be late. Also, it bothers other students. If you must come in late, be sure to do it quietly. Have your books out of your bag before you come into the classroom. Then go to your seat and sit quietly. In the US, it is not necessary to knock at the door before you come into the classroom.