阅读下面短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。
D
    In her outstanding book, “Choose the Happiness Habit”, Pam Golden wrote, “Take the story of two twin brothers for example. One grew up and became an alcoholic (酒鬼), while the other became a successful businessman. When asked why he became an alcoholic, the alcoholic replied, “Because my father was a drunk.” However, the successful businessman's answer was also “Because my father was a drunk.” when asked why he succeeded. The same background. The same upbringing (培养). However, the results were quite different. Why? The reason is that they had different choices. The brothers chose different thoughts which formed the situations they found themselves in at last, so they had different experiences.
    There was a time in my life when I thought difficulty was due to “bad luck”. Have you ever heard the saying “When it rains, it pours”? That was my answer when others asked me how things were going on when I was in trouble. So what do you think I got? “RAIN”. More and more “RAIN”. I couldn't understand why bad luck was always with me.
   Pam Golden says, “You're either living in the problem or you’re living in the solution.” Now, when I'm faced with what I used to think was a negative (消极的) situation, I use a different way to think about it. I force myself to replace those negative thoughts that make me lose heart in my mind with positive thoughts which encourage me to fight against the difficulty bravely. Sometimes I write down some ideas that may be a solution, which I combine with the lessons I have learned from the bad situations and the difficulties that troubled me in the past, and often, I find a solution to the problem soon. It seems that I should thank the difficulty I met with. The RAIN that poured in my world has become great experiences that provide me with valuable experience, from which I can benefit.
    Now, it doesn't “rain ” as much in my life as it used to. In fact, most days are beautiful, cloudless and sunny! Sometimes I do get a rain, but I think it makes me stronger just like the rain helps plants grow up.

一束光线从空气中，斜射入水中，与水面成30°角，其反射光线跟折射光线刚好垂直，则反射角是____，折射角是____．

生活的酸甜苦辣，会让我们产生多种情绪。以下对情绪描述正确的是（    ）

根据短文理解，选择正确答案。
A
    Shopping used to mean actually going to shops, but nowadays, you can shop without even leaving your house. Just sit in front of your computer, click your mouse and your things will be sent to your house in a couple of days.
November 11th is a big day for people who like shopping online. On that day last year, many online stores offered a big discount and free delivery service. The biggest online shopping sites in China, Taobao. com and Tmall.com, sold things worth 19.1 billion yuan in total.
    “Goods online are often much cheaper. It also saves me a lot of time. And we often have more goods on many online stores than in shopping malls,” Wang Xin, an online shopping lover in Beijing, said to China Daily. She stayed up very late for a lot of cheap goods online. She spent several thousand that day.
    Another big advantage of online shopping is that it helps people get things from different cities, even different countries, with ease. “I like eating duck neck very much and I often buy it on Taobao from shops in Wuhan. It's much more delicious than what our local (当地的) stores sell, but cheaper,” said Zang Xin, a girl in Yangzhou.
While enjoying online shopping, many people also have worries, especially for middle school student buyers. Young students are easily attracted by advertisements on the Internet and buy things they don't need.
    “Middle school students should pay more attention to their study. Searching for things wastes their time,” said Jing Chunling, an education expert. “Besides, online shop owners have no idea of the ages of their buyers. Anyone can easily buy things that they want to. Some of goods are even bad for young students such as cigarettes and wine.”

反应4CO（g）+2NO₂（g）⇌N₂（g）+4CO₂（g）开始进行时，CO的浓度为4mol/L，N₂的浓度为0，2min后测得N₂的浓度为0.6mol/L，则此段时间内，下列反应速率表示正确的是（   ）