Before I studied psychology, I used to think that people would laugh when funny things occurred. While I was right about that, I discovered there are lots of other psychological factors that make people laugh other than the funny part of a joke. When someone laughs at a joke, there will usually bemore than one reason that makes him laugh—and the more reasons there are, the more powerful the joke will be.

    I was attending a stand-up comedy show in Egypt, and when the man started to make fun of pedestrians crossing streets, everyone laughed their hearts out. The main reason those people strongly laughed was that almost allof them felt angry towards pedestrians who crossed streets carelessly. The joke wasn't only funny, it also made the audience feel that they were right about being angry at those pedestrians. That is, people were laughing both because ofthe funny joke and because of the happiness experienced as a result of the psychological support they got.

    The better a joke makes a person feel, and the more it includes other psychological factors, the more the person will like it. For example, if you envy one of your friends, and someone tells a joke that is funny and, at the same time, makes your friend seem stupid, then you will probably laugh atit louder than if you weren't jealous of him.

    In short, we don't laugh only when we hear something funny; we also laugh when we experience some kind of happiness that results from the other psychological factors involved in the joke. I strongly discourage making fun of anyone or belittling someone to make someone else laugh. All Iwant to explain is that if your joke supports a person's emotions, he will certainly like it a lot.

    If you see a group of people dancing and singing on the street or in the railway station, you don't need to feel surprised. They are a flash mob(快闪族), which is a group of people who come together suddenly in a public place, do something unusual for a brief period of time, and then quickly break up. They are usually organized with the help of the Internet or other digital communication network. At a predetermined(预先决定的) time, they gather and perform some distractions(消遣) such as waving their hands and exchanging books. Then, they quickly break up before the police can arrive. Using mobile phones, the flash mob can change its location if the first one has been replaced for any reason.

    Bill Lasik, senior editor of Harper's Magazine, organized the first flash mob in Manhattan in May 2003 and the first successful flash mob came together on June 3, 2003 —after the first attempt failed at Macy's department store. Lasik claimed that the activity was designed to make fun of hipsters(赶时髦的人), and call attention to the cultural atmosphere.

    Flash mob gatherings can sometimes shock people. Such an activity might seem amusing and untrue, but it also might frighten people who are not aware of what is taking place. Undoubtedly, flash mobs can serve as good political tools in any direction. They also have great economic potential, such as using flash mobs to advertise a product.

    The flash mob is now becoming more and more popular. People use it to do many things. For example, in 2009, Michael Jackson's fans took part in a flash mob to remember him. Hundreds of his fans gathered singing and dancing Michael's famous song “Beat It” together. Flash mobs give people from all walks of life an opportunity to come together to create a memory.

阅读下列短文，从每题所给的四个选项 （A 、B 、C  和 D ）中，选出最佳选项。

    A survey has shown that what you do on a plane can be determined by which nationality is listed on your passport.

    According to the results of an international passenger survey, Australians are the biggest drinkers on board with 36 percent choosing to down the hatch, compared to 35 percent of Americans and 33 percent of Brits.

    The Airline Passenger Experience Association(APEX) spoke to around 1,500 people, aged 18 and older, who have travelled by plane at least once during the last three months and were living in the United States, United Kingdom, Germany, Japan, China, Singapore, Australia and Brazil.

The results found Chinese travelers are most likely to nod off once the seat-belt sign switches off. They are also the first to take out their credit card for some in-flight shopping and the biggest fans of gaming. Americans on the other hand like to use their time in the air more productively—- when not drinking—- choosing to work while flying at 35,000 feet.

Meanwhile, Brits and Germans are the best at making chat with random strangers—-spending 50 percent more time than any other nationality. Comparatively, Brazilians conduct their conversations online via email, messaging apps or social media.

    Despite plane food having a bad reputation, seven out of ten interviewees said they were happy to eat up on the selection of in-flight snacks and meals. In-flight magazines were also popular with four out of five passengers.

    The international flyers did however express their desire for better in-flight entertainment. “The industry has greatly improved the comfort, entertainment and onboard service, and passengers are accepting those improvements” said Russell Lemieux, APEX executive director. “At the same time, passengers are demanding more from their air travel experiences which will drive more improvements touching all aspects of the journey. ” he added. 

Learn to cure cancer

    A vaccine for cancer is in the works.

    Lauren Landry and Chloe Tomblin are the scientists. They look in freezers(冰柜) for bacteria to use in the research. This research has its limitations—mostly because their lab is in a high school.

    But Lauren, 16, and Chloe,17 both students are Western Reserve Academy in the US, aren't put off by the difficulties they face in their cancer immunology(免疫学) class.

    “I hope we get to the point where we can get to a vaccine and write a paper,” Lauren said.

    Both conduct research into how to engage the immune system in stopping cancer from forming.

    Though the lab is in a high school, they don't use textbooks. The aim is to conduct real cancer research, either by testing the effects of substances on cancer cells or developing vaccines to target the growth of those harmful cells.

    The idea for the class came from Robert Aguilar, who has taught at the private school for many years. Students spend the first year learning research techniques. In the second year, students swap(调换) their blue lab coats for white ones. By this stage they are well into their research projects.

    “If first-years need any help, they can feel free to ask second-year students,” Aguilar said.

    Students form groups to conduct their research. One pair of students has researched the effect of capsaicin(辣椒素) on killing cancer cells. Another has tested the effect of caffeine(咖啡因) on the growth rate of breast cancer(乳腺癌) cells.

But few students get to the point in their research of experimentation with mice, Aguilar said. Lauren and Chloe hope that they can make decent progress in their work.

    “We know they're going to be used for good,” Lauren said. “If it does or doesn't work, it still has a huge impact.”

    Aguilar teaches the students that even research that doesn't work still contributes to science in some way. He tells students that “the best part of research is failing a lot”.

    The biggest challenge faced by travelers, especially those who like to have a backpacking trip is how to ensure a steady supply of clean clothes. Now, thanks to a great invention called Scrubba Wash Pack, that worry may be a thing of the past.

    The portable washing machine was invented by Ash Newland in 2010, while he was planning to climb Mt. Kilimanjaro. Struck by the limited packing space, he got inspiration from traditional washboards to create a bag that could be used to clean clothes. Then he quitted his career as a lawyer and focused on perfecting the bag's design. By 2012, the bag was ready for the public. It weighed only 180 grams and required very little storage space, making it perfect for anymore wishing to travel light.

    Not surprisingly, the bag which was worth 55 dollars was an instant hit with travelers, university students and even passengers. However, Newland was not satisfied. He still saw a disadvantage with his invention—dirty clothes had to be carried around in a separate bag! The recently introduced Scrubba Wash Pack solves that problem.

    In order to make the pack active, dirty clothes are placed inside the bag along with two or three liters of water. The bag is then shut tightly to ensure all air is squeezed out and the colors are massaged for a few minutes. After a quick wash, they are clean and ready to be dried. According to Newland, the pack can clean anything from jeans to smelly socks! What's even more amazing is that with a capacity to hold 13 liters of water, it can be used to wash more clothes at a time.

    The best part is that the 99-dollar pack that will be available for sale later this year, only weighs 300 grams and is completely foldable, making it easy to store when it's not in use. With the Scrubba Wash Pack, wandering through foreign cities searching for a washing shop, or paying for washing machines may soon be a thing of the past!

    A smile will tell people around you that you are a kind and friendly person. However, many people don't smile because they think they have ugly teeth. For example, one of my classmates, Mike, doesn't have very nice teeth, so that is why he seldom opens his mouth. He even says that he has lost confidence because of his teeth. So it is very important for us to look after our teeth. In fact, a lot of people have this problem. Some people inherit tooth problems from their parents, while others' teeth are damaged because of bad habits, like heavy smoking, eating too much sugar or not brushing teeth often. If your teeth are in bad shape, you should see a dentist and ask for help. They can help improve your teeth and tell you how to take care of them.

    Smiling can help you feel more confident and make people think of you as a more friendly person. If you want to keep healthy, you should not only smile but also laugh. An Indian doctor called Kataria said that young children should laugh about 30 times a day, while adults should laugh between 7 and 15 times a day. So please take this chance to smile and laugh now.