The kangaroo is the world's largest living marsupial (有袋动物). It was first found on the island of southwestern Australia. The animal was given its name by a famous English tourist in the 18th century.

    The kangaroo may be 7 feet(2.1m) tall when standing upright and the male can weigh as heavy as 200 pounds(90kg). The female (雌性) is smaller and lighter than the male. The kangaroo's head is small, but its ears are large, and its fore feet are really small. The animal has strong back legs and long tail.

    The kangaroo usually covers from 5 to 10 feet(1.5 to 3m) with each jump. The female is usually faster than the male. The mother kangaroo has a pouch (育儿袋) in its abdomen (腹部). The baby kangaroo grows up in the mother's pouch slowly.

    The kangaroo lives on grass and other plants. It is always moving from one place to another, lying down to sleep on the ground during the night. It likes to enjoy the warm sunshine. When it's in danger, it can use its back legs and strong tail to protect itself.

    Answer the following questions with No more than 6 words.

    Twenty years ago in Costa Rica, three girls found a baby sloth（树懒）on a road. The little animal's mother was killed by a car. These girls took the baby sloth to Judy, the owner of a hotel. Judy wanted to help, but she didn't know how to look after the sloth, so she called the zoo. With the help of the zoo, Judy took good care of the baby sloth. She named the baby sloth Buttercup.

    After her success, more people brought Judy wounded sloths or baby sloths they found. Judy then opened a rescue centre（救助中心）. Today, the rescue centre has saved more than 500 sloths. Sloths live in the forests of Central America and South America. They hang on to the trees with  their claws（爪子）. There are two main types of sloths. You can tell them apart by the number of their claws. Sloths hardly move. They spend most of their time sleeping in the trees.

    But now, with the increase of population, human beings（人类）cause a lot of problems for these slow and quiet animals. The main problems is that the forests are becoming smaller and smaller. When trees are cut down, sloths will fall and break themselves. Sloths who live near human beings sometimes are hit by cars or attacked by dogs.

    At the centre, workers care for the injured animals. Their goal is to help the sloths return to the wild when are healthy enough.

    What does it mean to be green? "Green" is more than just a color. It also means taking special steps to protect the environment — the water, the land, and the air we breathe. Why green? Plants are green, and without them the earth wouldn't be such a lovely home for us human beings.

    Sometimes people call our society a "throwaway society". That means we are always throwing away old things and buying new ones. Many times, if you no longer need something, someone else just might need it. For example, if your brother is old enough not to play with his plastic bike, why not give it to another family who has a little kid so that they don't need to buy one? And one less large plastic toy doesn't need to be produced.

    Recycling （回收利用）has never been easier. Many organizations will pick it up right in front of your house and some towns even require （要求）it. Tell your mom or dad you want to become "Chief of Recycling" for your family. Now that you know what things you can recycle, find a place to keep them. Make sure you encourage everyone in your house to think whether things can be reused or recycled before they're thrown away.

    Almost everyone likes traveling. But next time before you travel around the world, take a look at your own backyard. Is there a place where you could plant a tree or put in a little fruit or vegetable garden? If so, get there and get your hands dirty. Then you can watch with pride as your tree takes root, and your garden plants grow into big plants full of ripe, red tomatoes or tiny, juicy blueberries. Who knew being green would taste so good?

    If you're ever apart from your children, a new study says just talking on the phone will help just as much as a hug(拥抱).

    If you're a parent who spends long hours on the job, you probably feel sorry for spending so much time away from your kids. But the results of a new study show that a mother's voice alone can be just as comforting to an anxious child as physical contact(接触).

    In an experiment, researchers from the University of Wisconsin Madison asked a group of girls between the ages of 7 and 12 to solve math problems in front of judges—a stressful situation for anyone. Before the girls were set to give their answers, the researchers measured their levels of two hormones(荷尔蒙): cortisol, which goes up during stressful periods, and oxytocin, the "love" hormone, which goes down at the same time.

    After the girls finished the problems, some of them got to meet up with their mothers right away. The moms came in and hugged the girls. Another group of the girls didn't see their mothers, but received phone calls from them, in which their mothers told them how well they'd done. The final group had no contact with their mothers, but instead watched an animal movie, March of the Penguins.

    Finally, the girls' hormone levels were measured again. Although the movie was interesting, it did nothing to reduce the children's anxiety—but, surprisingly, both the physical contact and phone calls from their mothers had the same effect on reducing the girls' stress levels.

    So, no matter how old you are, if you're feeling stressed about something in your life, a phone call to Mom might be just the key to help you feel better.