Before birth, babies can tell the difference between loud sounds and voices. They can even distinguish their mother's voice from that of a female stranger. But when it comes to embryonic learning(胎教), birds could rule the roost. As recently reported in The Auk: Ornithological Advances, some mother birds may teach their young to sing even before they hatch(孵化)。New-born chicks can then imitate their mom's call within a few days of entering the world.

    This educational method was first observed in 2012 by Sonia Kleindorfer, a biologist at Flinders University in South Australia, and her colleagues. Female Australian superb fairy wrens were found to repeat one sound over and over again while hatching their eggs, When the eggs were hatched, the baby birds made the similar chirp to their mothers—a sound that served as their regular “feed me!”call.

To find out if the special quality was more widespread in birds, the researchers sought the red-backed fairy wren, another species of Australian songbird. First they collected sound data from 67 nests in four sites in Queensland before and after hatching, Then they identified begging calls by analyzing the order and number of notes. A computer analysis blindly compared calls produced by mothers and chicks, ranking them by similarity.

    It turns out that baby red-backed fairy wrens also emerge chirping like their moms. And the more frequently mothers had called to their eggs, the more similar were the babies' begging calls. In addition, the team set up a separate experiment that suggested that the baby birds that most closely imitated their mom's voice were rewarded with the most food.

    This observation hints that effective embryonic learning could signal neurological(神经系统的) strengths of children to parents. An evolutionary inference can then be drawn.“As a parent, do you invest in quality children, or do you invest in children that are in need? ”Kleindorfer asks. “Our results suggest that they might be going for quality. ”

    Bamboo is one of the world's most useful plants. For thousands of years, bamboo has been used in many different ways-from food to medicine to clothing and, in small ways, as a building material.

    However, bamboo is not often used as a building material in the developed world. A professor at the University of Pittsburgh in Pennsylvania is trying to change that. The professor and his students are testing the strength of bamboo.They are testing how much pressure or weight it can take before breaking.

    Kent Harries is a professor at the University of Pittsburgh. Harries says that testing methods for bamboo need to be the same for all. They need to be standardized. Standardizing test methods for bamboo will help to bring the plant into common use. It will also give engineers and builders around the world a dependable standard.

    Harries says that bamboo is strong in nature. The strength of at least three species of bamboo is similar to steel.Besides its strength, bamboo has other features that make it very useful in building. He says it is resilient(有弹力的), meaning it keeps its shape and strength even under pressure.

    Bamboo also grows quickly. Bamboo that is suitable for construction needs much less resources than wood. The harvest cycle of bamboo is about 3 years. Softwoods such as cedar, pine and spruce have a harvest cycle of about 10 years. And hardwoods that come from flowering plants such as oak and walnut need more than 30 years.

    Bamboo is widely used as food for panda bears. It is also used for flooring and window covers. However, for building, bamboo is not used much outside its native growing area. This is mostly because of its round shape. But there are other reasons too. People think -- or have the mentality--that bamboo is a low quality building material.

    Can you imagine walking into a gym and seeing dogs lifting weights or cats jogging? We're being a bit silly thinking of dogs and cats going to the gym, but we do have a reason. Just like human beings, pets that don't get enough exercise can become overweight.   
   Overweight pets can develop serious health problems just like we can. So, if you have a pet, part of being a good owner is making sure that your pet gets the right amount and kind of exercise.

    Before you start your pet on an exercise program, be sure to schedule a check-up for your pet and ask your veterinarian how much and what type of exercise your pet needs.

    Just like humans, pets need to be started out slowly. Over time, they will get fit and be able to exercise for longer periods of time. If you exercise alongside your pet, you'll benefit, too!

    Starting out, you might want to play with your pet for 15－20 minutes at a time. Gradually, you can turn those plays into several 30－minute walks or jogs each week. If your pet is especially active, you can extend them to an hour or longer.

    Of course, some pets, such as cats, may not be easy to take for a walk or a run. These pets still need exercise, though. Don't underestimate the value of energetic indoor play, such as games of chase, for these types of pets.

    As you start exercising with your pet, here are some things to keep in mind:

    Make sure your pet has plenty of water before, during, and after exercising.

    If you have older pets, don't push them as hard.

    Watch the heat! If you are outside, exercising with your pet will be best early in the morning or later in the day.

    Getting less sleep has become a bad habit for most American kids. According to a new survey(调查) by the National Sleep Foundation, 51% of kids aged 10 to 18 go to bed at 10 pm or later on school nights, even though they have to get up early. Last year the Foundation reported that nearly 60% of 7- to 12-year-olds said they felt tired during the day, and 15% said they had fallen asleep at school.

    How much sleep you need depends a lot on your age. Babies need a lot of rest: most of them sleep about 18 hours a day! Adults need about eight hours. For most school-age children, ten hours is ideal(理想的). But the new National Sleep Foundation survey found that 35% of 10- to 12-year-olds get only seven or eight hours. And guess what almost half of the surveyed kids said they do before bedtime? Watch TV.

    “More children are going to bed with TVs on, and there are more opportunities(机会) to stay awake, with more homework, the Internet and the phone,” says Dr. Mary Carskadon, a sleep researcher at Brown University Medical School. She says these activities at bedtime can get kids all excited and make it hard for them to calm down and sleep. Other experts say part of the problem is chemical. Changing levels of body chemicals called hormones not only make teenagers' bodies develop adult characteristics, but also make it hard for teenagers to fall asleep before 11 pm.

    Because sleepiness is such a problem for teenagers, some school districts have decided to start high school classes later than they used to. Three years ago, schools in Edina, Minnesota, changed the start time from 7:25 am to 8:30 am. Students, parents and teachers are pleased with the results.

    When I lived in Spain, some Spanish friends of mine The family you have chosen decided to visit England by car. Before they left, they asked me for advice about how to find accommodation. I suggested that they should stay at 'bed and breakfast' houses, because this kind of accommodation gives a foreign visitor a good chance to speak English with the family. My friends listened to my advice, but they came back with some funny stories.

"We didn't stay at bed and breakfast houses," they said, "because we found that most families were away on holiday."

I thought this was strange. Finally I understood what had happened. My friends spoke little English, and they thought 'VACANCIES' meant 'holidays', because the Spanish word for 'holidays" is 'vacancies'. So they did not go to house where the sign outside said 'VACANCIES', which in English means there are free rooms. Then my friends went to house where the sign said 'NO VACANCLES', because they thought this meant the people who owned the house were not away on holiday. But they found that these houses were all full. As a result, they stayed at hotels!

We laughed about this and about mistakes my friends made in reading other signs. In Spanish, the word 'DIVERSION' means fun. In English, it means that workmen are repairing the road, and that you must take a different road. When my friends saw the word 'DIVERSION' on a road sign, they thought they were going to have fun. Instead, the road ended in a large hole.

English people have problems too when they learn foreign languages. Once in Paris, when someone offered me some more coffee, I said "Thank you" in French. I meant that I would like some more. However, to my surprise the coffee pot was taken away! Later I found out that "Thank you" in French means "No, thank you."

    College students may find a greener campus when they return to classes this fall. Some schools arc repairing older buildings and constructing new ones that arc better for the environment. Other steps include adding wind and solar energy systems and planting vegetable gardens.

    George Washington University（GW）is a private school with 200.000 students. The university has two gardens where students volunteer their time.

    Over the last ten years GW has developed projects in three main areas-climate, water and eco-systems. They have begun to create projects on the ground to address climate change, They are planning on becoming carbon-neutral（平衡的）and, in fact, reducing the footprint by forty percent by 2025, from creating solar hot-water systems on our rooftops to making our buildings much more energy efficient. The school also offers 140 different classes in sustainability （可持续性发展）and the environment.

    Mark Orlouski said. "We see numbers like less than 20% of school having a green building policy five years ago, and now upwards of 80% of schools having a policy, which states that their new buildings will be built in a green fashion.

    GW is located in the Foggy Bottom neighborhood of Washington. Some neighbors say that while GW is laying to be Friendlier to the environment, it could also be a better friend to the neighborhood. The school has expanded quickly and there have been tensions between students and local residents