Johnny Smith was a good math student at a high school. He loved his computer. He came home early every day, then he worked with it till midnight. But Johnny was not a good English student, not good at all. He got an F in his English class. One day after school Johnny joined his computer to the computer in his high school office. The school office computer had the grades of all the students: the math grades, the science grades, the grades in arts and music, and the grades in English. He found his English grade. An F! Johnny changed his English grade from an F to A. Johnny' parents looked at his report card. They were very happy.

    "An A in English!" said Johnny's Dad. "You're a very clever boy, Johnny."

    Johnny is a hacker (黑客). Hackers know how to take informationfrom other computers and put new information in. Using a modem, they join their computers to other computers secretly. School headmasters and teachers are worried about hackers. So are the police, for some people even take money from bank computer accountand put it into their own ones. And they never have to leave home to do it! They are called hackers.

    Tornadoes are nature's most violent storms, which can cause deaths and destroy a neighborhood in seconds. A tornado appears as a funnel-shaped (漏斗状) cloud from a thunderstorm to the ground with whirling (飞快移动) winds that can reach 300 miles per hour. Damage paths can be over one mile wide and 50 miles long. Every state is at some risk from this disaster.

    Some tornadoes can be seen clearly, while rain or nearby low-hanging clouds obscure others. At many times, tornadoes develop so rapidly that little, if any, advance warning is possible.

    Before a tornado hits, the air may become very still. A cloud of debris (散片) can mark the location of a tornado even if a funnel can not be seen. Tornadoes generally occur near the edge of a thunderstorm, when the strong wind may die down. It is not uncommon to see clear, sunlit skies behind a tornado.

The following are facts about tornadoes:

    The average forward speed of a tornado is 30 MPH, but may also vary from still to 70 MPH. Debris is picked up or a cloud forms in the funnel.

    The average tornado moves from southwest to northeast, but tornadoes have been known to move in any direction. Tornadoes are most often reported east of the Rocky Mountains during spring and summer months.

    Tornadoes can happen together with tropical storms and hurricanes as they move onto land. Waterspouts are tornadoes that form over water.

    The tornado season in the southern states of America is March through May; in the northern states, it is late spring through early summer. Tornadoes are most likely to occur between 3 p.m. and 9 p.m., but can occur at any time.

    Parents whose children show a special interest in a sport feel very difficult to make a decision about their children's careers. Should they allow their children to train to become top sportsmen and sportswomen? For many children it means starting schoolwork very young. And going out with friends and other interests have to take a second place. It's very difficult to explain to a young child why he or she has to train five hours a day, even at the weekend, when most of his or her friends are playing. Another problem is of course money, In many countries money for training is available from government for the very best young sportsmen and sportswomen. If this help can not be given, it means that it is the parents who have to find the time and the money to support their child's development and sports clothes, transport to competitions, special equipment, etc. All can be expensive.

    Many parents are worried that it is dangerous to start serious training in a sport at an early age. Some doctors agree that young muscles may be damaged by training before they are properly developed. Professional trainers, however, believe that it is only by training when young that you can reach the top as successful sports person. It is clear that very few people do reach the top, and both parents and children should be prepared for failure even after many years of training.

    In Alaska, the US, the grizzly bears are not alone because of Timothy Treadwell. Everyone knows that grizzly bears can be very dangerous to people. However, people can be perilous to grizzly bears, too, because their fur and food are beneficial for some people. In fact, half of the grizzly bears die before they are five years old, even though they can live for about 30 years.

    Grizzly bears hibernate every winter. They sleep for several months. During this period, they don't wake up or eat anything. When they wake up in the spring, the grizzlies are in danger. But Timothy can protect them. He sleeps in a tent near the bears and bathes in a river with them. People do not hurt the bears when Timothy is with them.

    Timothy went to Alaska for the first time about 17 years ago. He was attracted by the beauty of the land and the prettiness of the animals. When he learned that people kill many grizzly bears every year, Timothy determined to protect the grizzly bears and to keep the bears safe from danger, so he lives with the bears for four to five months every year. At the beginning, Timothy's parents didn't agree, but later, they firmly supported him to do so, because they also wanted to protect bears as him.

    Timothy has lived with the grizzlies every spring for about 17 years. Some bears are now his friends. He gave them names. His friend Booble sometimes gives him fish which he likes. His friend Lazy sleeps near his tent every night. Every winter, when the bears hibernate, Timothy returns to his home in California. Then he teaches children and adults about his friends in Alaska.

    WeChat, the Chinese social media smartphone app, saw an increase in user numbers of 41 percent year on year to 500 million at the end of last year, in a sign that parent company Tencent is extending its reach for the mobile Internet. As one of the largest Internet integrated service providers in Chinaand one of the most Internet users in China, Tencent's profit grew 24 percent to RMB 20.98 billion per year, slightly higher than forecasts, driven mainly by online gaming profits. It is unclear how much WeChat contributed to Tencent's profits but the app's growth is a strong indicator of the company's long-term health as it tries to adjust its business to be more suitable for mobile devices.

    "We extended our leadership in games and online media, and made breakthroughs in emerging platforms such as online security and mobile payments." Ma Huateng, Tencent chairman, said in a statement. WeChat is the second highest ranked social app in China, behind QQ, Tencent's another chatting app, which claimed to have 815 million registered monthly users at the end of 2014.

    Tencent has been unwilling to earn money through WeChat by flooding it with advertising, which could influence the users' experience. But this is expected to change. Some analysts anticipated(预期) that advertising would be introduced on a large scale later this year. Early attempts to test ads on the service have not always gone smoothly. After a BMW ad was introduced on some users' feedbacks in January, many users who were not targeted by the brand's marketing complained of "discrimination" by Tencent's data mining algorithm(数据挖掘算法). They claimed it unfairly treated them as not wealthy or successful enough to view the BMW ad.

    In the US and Britain, the slogan around colleges was "Save water. Shower with a friend." Now, Wuhan University has come up with another system for the campus bathhouse. It charges students for the amount of time in a shower. Before entering the bathhouse, students pay for the amount of time they want in the shower with cash or their student ID card. The clock starts ticking the minute the tape is turned on. It pauses when a button is pressed for soap. An integrated circuit (IC) card reader at each tap shows the time. No money, no water. The benefits of the new system can be seen with the old system, which charged 1 yuan for each person regardless of time in the shower. The university used about 320 tones of water daily under the old system, but only 160 tons now.

    Many students use the new system but opinions on it are divided. Some students say it is bad because bathing had become a sort of race. Many people using it for the first time are not sure how long they need to shower. Some might be embarrassed if their time is up and they're still covered in soap. They have to ask the bathhouse worker to help them buy extra time.

    "It's a flaw in the system that you can not buy extra time on the ID card," said Ren, a freshman in Wuhan University. The university is also considering some students' suggestions that they be allowed to pay after they've finished the shower. Not surprisingly, some are complaining about losing the hour shower. But many students say the move helps them develop a water-saving sense.

    Without the time limits, most students tended to shower for 30 to an hour in the bathhouse.

    Some even used the hot water to wash their clothes. "In my experience, 10-20 minutes is enough," said Dai Zhihua, a third-year student who usually takes 8 minutes.

    A similar system has been installed in other universities. Shanghai Normal University introduced it at its Fengxiang Campus in September. The bathing fee there is 0.2 yuan per minute. One male student responded by setting a record with a two-minute shower.