There are world records at the Olympic Games. But what are the word records in animal kingdom?

    The largest and heaviest animal on earth is the blue whale. It weighs between 110 and 120 tons. Its heart is the size of a Mini Cooper, It's got the biggest mouth in the world as well. About 100 people can fit inside it. But it doesn't eat people! In fact, the biggest thing it can eat is the size of an apple.

The giraffe is smaller than the blue whale but it is also a record breaker. It's the tallest living land animal. It's got the longest neck-about 2 metres long, and it's got the longest legs-about 1.8 metres long. Drinking is difficult, but eating from the top of trees is easy! And its tongue is 50 c m long!

    The most dangerous animal in the world isn't a lion or a bear. It's an insect! The mosquitoes (蚊子) that carry malaria kill over 1 million people a year. After that, the most dangerous animal is the venomous snake. They kill 50,000 to 125,000 people a year.

     A. the mosquito           B. the giraffe                C. the blue whale

    What is the first thing you want to do when you see someone yawn(打哈欠)? You want to yawn, too! Yawning is contagious.

    Scientists have found that all people yawn. Babies start to yawn even before they are born. The earliest yawn takes place when a baby is still inside its mother. When young children are about one year old, they start to yawn when they see others yawning. That's why scientists seem to think yawning is contagious.

    It's no secret that yawning is contagious, but why do we yawn? Well, scientists are not really sure.

    Some think we yawn because we feel bored. Recently scientists studied two groups of students between the ages of 17 and 19. One group watched music videos, and the other watched a boring color test. Scientists compared the numbers of their yawns and found that the color test group yawned more times than the video group.

    Another reason about yawning has to do with breathing. Some scientists believe that when we are bored or tired, we breathe more slowly. As our breathing slows down, we cannot get rid of(去除) enough carbon dioxide (CO₂) in our bodies. When there is too much carbon dioxide, our bodies will tell the brains (大脑) to breathe deeply. The result is a big yawn.                                                           

    In 2007, scientists suggested a new reason. They said that the reason people yawned was to cool down their brains. These scientists found that people who were warmer than others yawned more often.

    Scientists are still trying to find out why yawning happens and why it is so contagious. But they are only sure that when one person yawns, almost everyone else nearby wants to yawn, too.

    Many people have dogs at home as pets. If a dog is happy, then he may want to meet you or play with you. If he doesn't feel happy, then he would rather stay alone. But dogs can't talk. How can you tell how your dog is feeling? By his body language.

    If your dog's head and back are lowered, his ears are down and his eyes are narrowed, and his tail is between his legs, then he is fearful. You may touch him gently to comfort him. If your dog's ears are up, his eyes are bright, and he wags his tail rapidly (快速地), he is very happy. He may also hold his mouth open more or even pant (气喘) mildly. Then you can go and play with him freely. If he closes his mouth and looks serious as you get closer, then he has changed his mind. It is better to leave him alone until he comes to you. Remember, we are talking about dogs that you know. Be sure a parent is around to allow you to get close to the dog. Get away from strange dogs even if they seem friendly.

    The most important clue (线索) is the mouth. If the dog's mouth is closed, then he is most likely to be not relaxed or happy, and he does not want you to touch or play with him right now.

    Why is music so important to children? Here are some of my thoughts on the subject.

    Music has a positive（积极的） effect on young children's development!

    New research shows that music has a good influence on young children's cognitive（认知的） skills, such as spatial reasoning（空间推理） and memory. Research also shows that offering children an interesting environment can support children's healthy growth and development.

    Young children enjoy making music with others!

    Making music with others gives children a wonderful feeling of belonging to the group. Children might have difficulty joining in activities with others because they are shy, have limited language ability or special needs, but they can freely take part in a music activity.

    Music makes young children happy!

    Children seem to experience much pleasure and joy when listening to music, making music and dancing to music. Whether they are singing along to a CD, playing an instrument or dancing to music around the classroom, most children seem to thoroughly（彻底地） enjoy participating in a music activity. How wonderful it is to offer children the chance to do some activities about music!

    The world's first hydrogen-powered(氢动力) trains have begun running in Germany last month. The new trains will run 100-kilometer trips and can travel up to 140 kilometers an hour.

    A French railroad company called Alstom built two hydrogen-powered trains. Teams in Germany and France cooperated on the project, which was supported by the German government. The new train model, called the Coradia iLint, signals the beginning of efforts in Germany and other nations to move away from pollution-producing diesel(柴油) trains.

    Compared(与…相比较) with diesel trains, the Coradia iLint is designed to run on non-electrified train lines with low levels of noise. It uses a process that combines hydrogen and oxygen to produce electrical power. If the system produces more energy than the train needs at that time, it can store the extra energy in batteries. The only emissions(排放物)are water and steam.

    A single tank of hydrogen can run a Coradia iLint train for about 1,000 kilometers. This is very similar to the distance a diesel-powered train can run on with a single tank.

    Hydrogen-powered trains cost more than diesel trains to build. But Alstom officials say the operating costs are much lower. The company plans to provide another 14 Coradia iLint trains by the year 2021. Several other European countries have also expressed interest in developing hydrogen train systems. France has already said it wants its first hydrogen train to be operated by 2022.