user: Problem: 
Q: Read the following article and answer the question. Article: A trip across the Pacific will guarantee you a different experience with a tipping  culture you've never come across in China. In the US, giving a little extra money to service workers on top of your bill is a common practice. Though US national law requires that businesses pay workers at least $7.25 (45 yuan) per hour, employees receiving tips--often waiters and waitresses--are the exceptions. They usually only receive at least $2.13 an hour, and tips make up the difference. As theWall Street Journalput it, "The American system of tipping holds the promise of great rewards for waiting staff." So how should you tip if you are in the US. Normally you pay tips as a percentage of the bill. Offering an extra 15 percent of the bill to the waiter or waitress in a restaurant and to the delivery man or woman is customary and expected. You can offer more for great service and less for poor service. Yet there is an exception. For take-out food, you don't have to provide tips, though some people say that filling an order still requires work and time that deserve a little extra--but maybe a little less. Tips are not expected at fast food restaurants, cafes or ice cream shops either, though a tip jar might be right by the cash register  . Don't feel _ to throw some money in, but also remember that it doesn't hurt. Those workers do not rely on tips. Other service workers also receive tips. For taxi drivers, 15 percent is the norm  , more if they help with your bags. Hairdressers often receive about 15 percent of the bill. The same goes for spa therapists  and tour guides. Today, you can even pay tips on a credit card. When receiving a copy of the bill to sign, you are free to fill in how much you'd like to tip. Though thinking about when to tip and how much you should tip causes a big headache for many Chinese people, it's important to bear in mind that as long as you show respect and use your reasoning, things will be just fine. Question: What is the article mainly about? Answer:
Answer: How to giving tips properly in the US.
Problem: 
Q: Read the following article and answer the question. Article: How You Can Learn a Language in Only 10 Days Most people recognize the many benefits of learning a foreign language: You can travel to foreign countries and feel comfortable, be a more productive and attractive employee in today's competitive job market, and immerse  yourself in the vast cultures around the world. In addition, scientific studies have shown that learning a new language helps to keep memories sharp and naturally improves brain function. But do you know that you can learn a new language in as little as 10 days? The Pimsleur Approach to learning new languages help users pick up new languages quickly .Even the FBI and National Security Agency have purchased the Pimsleur Approach. The Pimsleur Languag Programs The entire Pimsleur Approach is what language learning should be : quick, fun and easy. You will learn a new language effortlessly without any reading, writing or computer use. The Pimsleur Approach has a 100 percent guarantee : speak in 10 days or you don't pay. Who is Dr. Pimsleur? Pimsleur Approach is a language educator. He noticed that children have an amazing ability to learn new languages quickly. He spent his life developing this course to let you , as an adult , learn a new language as easily as a child would .You might not realize it , but you have already learned one language using the Pimsleur Approach. Limited availability of special offers The company is currently offering new customers a special offer of 50 % discount on tuition fees.The programs which normally cost $100 are now available for just %50. Better yet ,they are also offering a money-back guarantee. So ,if you find you are not learning as fast as they said , simply return it for a full payment . For more information , please click here. Question: Where can we most probably find the passage ? Answer:
Answer: On the Internet
Problem: 
Q: Read the following article and answer the question. Article: What was your favorite sport during your childhood? Maybe running around the playground or jumping rope for hours would bring you pleasure. At that time you weren't thinking of health, you were just thinking of entertainment . But in this age of high-tech home equipment, the simple joy of jumping rope has been forgotten. I think rediscovering it probably will give you a total-body exercise. Although considered an excellent form of exercise, jumping rope has never been widely accepted because of two reasons. First, most people consider jumping rope to be an excellent form of cardiovascular   exercise, but they also believe that it is simply too difficult. In other words, they don't think they'll be able to continue jumping for the near 20 minutes in order to achieve a beneficial physical effect. Second, many  people regard it as a little boring and overly repetitive --not as something fun or enjoyable.  _ . Instead of doing the usual two-foot bounce  over and over again, players good at rope-jumping often change their pattern every 10 or 20 jumps. A single bounce, a double -bounce, a skip, a knee-up, side swings, as well as a variety of other easy-to-learn free-style rope-jumping . Nowadays researchers are discovering that jumping rope also prepares the brain for learning. It is an exercise allowing both brain hemispheres to perform equally to each other . In a word, jumping rope can be a life-long activity requiring little equipment, time and space, yet leading to a much healthier life. Question: One reason that can explain why rope jumping has not spread widely is that  _  . Answer:
Answer:

assistant: it is believed to be boring and repetitive