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    Have you ever wondered why the roots of the plants always know which way to grow—into the soil but not above it? Some British scientists have recently solved this mystery.    

      It turns out that roots have special hairs that tie them into the soil and help them grow their way past obstacles, a team at the John Inners Center in Norwich reports in the February 29 issue of Journal Science.

    "The key is in the fuzzy(有绒毛的) coat of hairs on the roots of plants," says professor Liam Dolan. "We have found a growth control system that enables these hairs to find their way and to become longer when their path is clear."

    Root hairs explore the soil in much the same way a person would feel their way in the dark. If they come across an obstacle, they make their way around until they can continue growing in an opening. I the meantime, the plant is held in place as the hairs grip the soil.

    The hairs are guided by a clever chemical trick. A protein(蛋白质) at the tip of the root hairs called RHD2 helps them to take calcium(钙) from the soil. Calcium makes the hairs grow, and produce more RHD2, and take more calcium.

    But when an obstacle blocks the hair's path, or the hair reaches the surface of the soil, the cycle is broken and growth starts in another direction.

    This system gives plants the flexibility to explore a complex environment and to live in even the most unpromising soils, says Dolan.

    In poor soils such as in parts of Australia and Africa, native plants have adapted by producing enormous numbers of root hairs. A better understanding of this adaptation will allow scientists to develop hairy rooted crops that can grow in unfriendly environments.

    According to Dolan, "Research in the John Inners Center is taking a breeding approach(育种方法) to increase hair length in wheat but it will be some time before new cultivars(栽培变种) are developed."

    US people are overweight, eat lots of fast food and fill their homes with pets. At least that's what 21 European teenagers think.

    The students, 18 from Germany and 3 from France, are exchange students. They are studying in the US for a year. After a few days in the US, they said what they thought about the country.

    Most talked about the amount of fast food US people eat. It's not that the students don't eat fast food. They just don't eat as much.

    Laetitia Villeneuve from France said she eats fast food, usually McDonald's, only once or twice a year.

    "I like it," said Nora Koeberle from Germany. "But I couldn't eat it every day. I'd get fat. "

    Students are surprised at how big US people seem.

    "There are fat people in Germany," said Antonia Greimel from Germany. "But not as many as there are here."

    They also spoke about the animals. Silvana Wolfram from Germany said she had heard about how people had lots of pets in the US.

    Other ways of US high schools interested the students.

    For example, Koeberle said she wouldn't be able to play an instrument or sports as part of her classes in Germany. She can in the US.

    But the best thing about US high schools is something the European kids can't get back home. "I do wish we had parties," Koeberle said.

    Should you work out in the gym in the morning instead of in the evening? It all depends. Of course, there are advantages of working out(运动) in the morning.

    You will increase your energy for the rest of the day. “Morning workouts result in better energy levels throughout the day and give you more mental sharpness,” says Dr. Cedrie Byrant, Chief Science Officer of the American Council on Exercise.

    Here is another advantage. In 2017, health researchers found that exercising in the morning helps you sleep better at night. According to the study, in all cases, those who exercised at 7:00am experienced about a 10 percent drop in blood pressure that carried through the rest of the day. They also had about a 25 percent drop in blood pressure at night, slept longer and had more beneficial sleep cycles than when they exercised at other times of the day.

    However, there are disadvantages, too.

    If you are not an early riser, getting out of the bed in the morning can be very difficult. Byran says that if you're not used to exercising in the morning and force yourself to get up, you may not put as much effort into the exercise as you would later in the day. Also, if you aren't careful, you can damage your sleep schedule, which can lead to insufficient sleep.

    Besides, hitting the gym before work can cause a challenge in terms of scheduling. If you work a 9-to-5 job, getting ready for work and going to work can cut your morning workout short, Byrant notes.

    To sum up, it has both advantages and disadvantages. If it suits you better to work out in the morning, you can do so.

    Adopting (领养) a new pet should be an exciting and rewarding experience. But just as all families are different, so are all pets. Learn what to consider before you find your new furry family member.

    All pets require their owner's time, so Theisen, an expert in pet care, says how much time you can give to the pet is the top thing to consider. "If you adopt a 4-year-old cat, she's not going to need the same amount of care as a 9-week-old dog". says Theisen.

    Like dating and finding the perfect partner, you want a pet that shares your interests and activity levels, particularly if you're looking for dogs. "Consider activity levels in the family," says Theisen. "If you're a couch potato, or in other words, a homebody, look for a pet that matches that activity level."

    Some dogs, like Dalmatians and Terriers, can be loud and noisy and demand a more active lifestyle and room to be outside; they might not fit as well in close living situations as more sedentary pets. The Humane Society of the United States encourages potential owners to research books and websites and talk to other pet owners when considering adopting a new pet.

    Theisen says that potential owners should go beyond the first impression of loveliness and watch how the animals interact with them. "There are dogs that will jump to the gate to meet you," says Theisen. "And there are dogs that sit there with their sad doggy eyes — you know they're not going to be high-energy dogs".

    Some exotic pets, like tortoises and parrots, are likely to live longer than dogs and cats — and even their human owners. They can also grow to be much larger than they were when they first came to live with their owners. Owners should make sure that their living situations should be continually updated and also prepare for the animal's future.

    A couple had a son eleven years after they married. They were a loving couple and the boy was the apple of their eye. When the boy was around four years old, one day the father was very tired after work so he asked his wife to pick up their son. The mother, who was very busy in the kitchen, totally forgot about it.

    Later the boy lost his way on the street. When the son was found missing, the mother hurried to look for him, but she didn't find him. The mother felt very sad and didn't know how to face her husband.

    When the father went to the police station after hearing that the son was missing, he looked at his wife and said just four words. What do you think the four words were? The husband just said "I love you, darling."

    The son was missing. If he had picked him up earlier, this would not have happened. There is no point in blaming (责备) anyone. His wife had also lost her only child. What his wife needed at that moment was comfort and understanding from her husband. That is what the husband gave his wife. Several weeks later, with the help of the police, the couple finally found their lost son. The family's relationship became stronger over that time.

    Sometimes we spend lots of time asking who is to blame. We miss many chances to give each other support and let each other feel the warmth of human relationships. Get rid of all your unwillingness to forgive, selfishness, and fears and you will find the world is much more wonderful.

    A recent documentary produced by the British Broadcasting Corporation (BBC) has caused a stir in China and in the UK.

    The documentary, titled Are Our Kids Tough Enough? focuses on five Chinese teachers who are sent to teach 50 UK teens at a school in Hampshire.

    The teachers instruct the students for a month. The pupils are then tested, and the results are compared to the ones of those who have continued in the regular UK education system. The idea is to see if the Chinese method improves academic performance.

    The Chinese teachers use their own teaching methods but receive strong resistance from the students. A clip from the documentary online shows some problems, with Chinese teachers calling their students lazy and lacking in discipline, while the students say the high pressure and harsh teachers are driving them crazy.

    This has aroused a new debate in both China and the UK, with some arguing the teenagers need more regulation and discipline. Others say Chinese methods encourage rote learning (死记硬背) instead of independent thinking. For instance, Chinese language teachers should do more than pass on knowledge about words and characters. They should inspire students, helping them feel the sentiment from Chinese literature. This is a higher level of teaching.

    Yang Dongping, dean of the 21st Century Education Research Institute, says, "The Chinese teaching methods are designed to strictly train the majority. Foreign teaching methods, however, are more natural and relaxing, and designed to inspire students' interest in learning. Education methods are based on culture. That is why a successful education method in one place may not work that well when simply 'transplanted' into another place."

    Yang Dongping says, "The documentary does reflect some problems rooted in traditional Chinese teaching methods. Nobel prize winner, Yang Zhenning, gave a very fair comment on this issue. He said the Chinese-style education method works for most ordinary qualified students effectively, helping them reach high standards. However, it may weaken the training for high-potential outstanding students."