Look up in the sky. Do you see any clouds? What do they look like? Some clouds are fluffy(绒毛状的) and white, like cotton balls. Others are dark almost black, and make you hold an umbrella. At sunrise and sunset, clouds can look red, purple, or yellow—as if they were colored with crayons. But what are clouds anyway?

    You can't reach out and touch the clouds, but you can make your own in a bottle.

    You need

    * an adult helper

    * a huge, empty glass jar

    * a metal strainer(过滤器)

    * hot water

    * ice

    Do these

    Step1. Have your helper fill the jar with hot water, leave it there for two minutes, then pour out most of the water. Leaving just an inch or two at the bottom of the jar.

    Step2. It's your turn, put the strainer over the mouth of the jar, fill the strainer with ice. Watch the jar.

    What happened?

    A cloud formed in the jar! Some of the hot water at the bottom of the jar turned into hot water vapor(蒸汽). The water vapor rose and met with the cold air coming off the ice. When the water vapor condensed, it formed a cloud. Hot air rises and carries with it lots of water vapor, the higher the air rises, the more it cools down. Soon the cold air can't hold all the water vapor so it starts turning into tiny water drops, and becomes a cloud.

    No Car Day was first started by 34 cities in France on September 22, 1998. It was started to protect the environment. By now, more than 1,000 cities around the world have had a No Car Day.

    The first No Car Day in China was in Chengdu in 2001. Other cities, including Taipei, Shanghai and Wuhan, also support the day.

    In Beijing, more and more people are joining the campaign. It asks drivers to leave their cars at home for one day each month and walk or ride a bike to work. It also calls on Beijingers not to use cars on June 5(World Environment Day). The slogan for the day is, “If we drive for one less day, we can have one more nice day.”

    So far, more than 200,000 drivers have shown their support. “We can't control the weather, but we can choose not to drive,” said Wu Zonghua, a car club chairman. Beijing is trying to have 238 blue sky days this year. In the first quarter of 2012, Beijing only had 52 blue sky days. This was 11 days less than the number for the same period the year before. Much of the dust comes from the desert, but cars cause most of the air pollution. We must do more for No Car Day.

    Have you ever imagined going to other countries without your paper Passport? That will soon come true. And your paper passport will become history. You may use their new kind of passport

    It's reported that Australia will be the first country to use the cloud passport. With the cloud passport, you don't have to take a paper passport with you all the time. The cloud passport will have your name, photos and other information. And if you go to other countries, you can just check the information on the computer.

    When you take a paper passport with you, you might lose it. But with the cloud passport, you don't have to worry about that.

    Do you think the cloud passport is a great idea? Perhaps you will have it in the future, too.

    Why do we like drinking water from plastic bottles? Some people think it is healthy and clean. Others drink bottled water because it's easy--you can carry it around with you. In hot countries, like Greece, we often buy bottles of cold water in the summer.

    However, making tots of plastic is not a good idea for many reasons. First of all, we need a lot of oil for plastic products. We usually use oil as a source(资源) of energy. If we reduced the number of bottles we made, we wouldn't need so much oil. Plastic bottles also pollute the environment. If we recycled all our plastic bottles, we wouldn't need so much space for rubbish dumps. But in Greece, we don't recycle much of the plastic we use. In 2006, Greeks recycled only about 10% of plastic waste. The rest became rubbish on land and in rivers and seas.

    So next time you want to throw away a plastic bottle in the litter bin, stop and think. If you recycled it, you would help the environment. But what can you do when there isn't a recycling bin near you? Well, there are lots of useful ways that you can use your bottles again. For example, an empty bottle makes a great piggy bank for your pocket money, and if you cut a bottle in half, you will have a plant pot. Go green! You can make a difference.