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.

    Edmund Halley was an English scientist who lived over 200 years ago. He studied the observations of comets(彗星) which other scientists had made. The orbit of one particular comet was a very difficult mathematical problem. He could not figure it out. Neither could other scientists who dealt with such problems.

    However, Halley had a friend named Isaac Newton, who was a brilliant mathematician. Newton thought he had already worked out that problem, but he could not find the papers on which he had done it. He told Halley that the orbit of a comet had the shape of an ellipse.

    Now Halley set to work. He figured out the orbits of some of the comets that had been observed by scientists. He made a surprising discovery. The comets that had appeared in the years 1531, 1607 and 1682 all had the same orbit. Yet their appearances had been 75 to 76 years apart.

    This seemed very strange to Halley. Three different comets followed the same orbit. The more Halley thought about, the more he thought that there had not been three different comets, as people thought. He decided that they had simply seen the same comet three times. The comet had gone away and had come back again.

    It was an astonishing idea! Halley felt certain enough to make a prediction of what would happen in the future. He decided that this comet would appear in the year 1758. There were 53 years to go before Halley's prediction could be tested.

    In 1758 the comet appeared in the sky. Halley did not see it, for he had died some years before. Ever since then that comet had been called Halley's comet, in his honour.

    San Francisco Fire Engine Tours

    San Francisco Winery Tour

    Running: February 1st through April 30th

    This delicious tour goes through the city on its way to Treasure Island where we will stop at the famous Winery SF. Here you can enjoy 4 pours of some of the best wine San Francisco has to offer. (Included in ticket price)

    Departing from the Cannery: Tour times upon request

    Duration ( 时长 ) :2 hours

    Price: $90

    Back to the Fifties Tour

    Running: August 16th through August 31st

    This tour transports you back in time to one of San Francisco's most fantastic periods, the 1950s! Enjoy fun history as we take you through San Francisco for a free taste of ice cream.

    Departing from the Cannery: 5:00 pm and 7:30 pm

    Duration: 2 hours

    Price: $90

    Spooky Halloween Tour

    Running: October 10th through October 31 st Join us for a ride through the historical Presidio district. Authentic fire gear(服装) is provided for your warmth as our entertainers take you to some of the most thrilling parts of San Francisco.

    Departing from the Cannery: 6:30 pm and 8:30 pm

    Duration: 1 hour and 30 minutes

    Price: Available upon request

    Holiday Lights Tour

    Running: December 6th through December 23rd

    This attractive tour takes you to some of San

    Francisco's most cheerful holiday scenes. Authentic fire gear is provided for your warmth as you get into the holiday spirit.

    Departing from the Cannery: 7:00 pm and 9:00 pm

    Duration: 1 hour and 30 minutes

    Advance reservations required.

    People have grown taller over the last century, with South Korean women shooting up by more than 20cm on average, and Iranian men gaining 16.5cm. A global study looked at the average height of 18-year-olds in 200 countries between 1914 and 2014.

    The results show that while Swedes were the tallest people in the world in 1914, Dutch men have risen from 12th place to claim top spot with an average height of 182.5cm. Latvian women, meanwhile, rose from 28th place in 1914 to become the tallest in the world a century later, with an average height of 169.8cm.

    James Bentham, a co-author of the research from Imperial College, London, says the global trend is likely to be due to improvements in nutrition and healthcare. "An individual's genetics has a big influence on their height, but once you average over whole populations, genetics plays a less key role," he added.

    A little extra height brings a number of advantages, says Elio Riboli of Imperial College. "Being taller is associated with longer life expectancy," he said. "This is largely due to a lower risk of dying of cardiovascular(心血管的)disease among taller people."

    But while height has increased around the world, the trend in many African countries causes concern, says Riboli. While height increased in Uganda and Niger during the early 20th century, the trend has reversed in recent years, with height decreasing among 18-year-olds.

    "One reason for these decreases in height is the economic situation in the 1980s,"said Alexander Moradi of the University of Sussex. The nutritional and health crises that followed the policy of structural adjustment, he says, led to many children and teenagers failing to reach their full potential(潜力)in terms of height.

    Bentham believes the global trend of increasing height has important implications "How tall we are now is strongly influenced by the environment we grew up in," he said. "If we give children the best possible start in life now, they will be healthier and more productive for decades to come."

Comparing college entrance exams, there are different needs for admission. The national college entrance examination, or gaokao, is known as the most competitive test for Chinese students. Do students in other countries also need to take a standardized test to get into university?

South Korea holds the College Scholastic Ability Test（CSAT） in November each year. The CSAT plays an important role in the country's education. On test day, bus and subway frequency increases to make sure that students can get to the test sites in time.

Japan is trying to reform its standardized national college entrance exam. In January 2022, Common Test for University Admissions took the place of the National Center Test for University Admissions, which had been adopted since 1990. The new exam aims to put emphasis on the ability of students to discover and solve problems by themselves.

The American College Test（ACT） and Scholastic Assessment Test（SAT） are the two main college entrance exams taken by students in the US. While SAT tests a student's ability to learn, the ACT tests a student's educational development. Both tests normally take place seven times throughout the year. Students can retake the exams for a better score.

In the UK, there's no standardized test for college admission. Instead, each college has their own admission criteria. These criteria often onlyinclude submission of transcripts（成绩单） and participation in an interview. Yet, there are subject-specific exams used by some colleges.