There is little rain in desert. Because deserts are so dry, they have no "quilt" to help stop the soil from going away. As a result, they may get very hot during the day with the sun shining, but don't hold the heat overnight. Many deserts can quickly get cold once the sun goes down. Some deserts can reach temperatures of over 100 degrees F during the day and then drop below freezing (32 degrees F) during the night.

The largest hot and dry desert in the world is the Sahara Desert in Northern Africa. The Sahara is a sandy desert with great sand hills. It covers over 3 million square miles of Africa. Other large deserts include the Arabian Desert in the Middle East, the Gobi Desert in Northern China and Mongolia, and Kalahari Desert in Africa.

Animals that live in the desert are also used to needing little water. Many get all the water they need from the food they eat. Other animals keep water that they can use later. The camel stores up fat in its hump while other animals keep something they need in their tails.

Only certain types of plants can live in the terrible environment of the desert. You won't see a lot of tall trees in the desert. Most plants have a way to keep water in their leaves, or trunks so they can live a long time without water.

Now deserts cover around 20% of the world's land, but they are growing. This is called desertification and is caused by different reasons including human activities. The Sahara Desert is growing larger and larger each year. What should we do with it ?

    March 20th is World Water Day every year. According to a report from the United Nations, more than half of the world's major rivers have serious water loss and are polluted.

    The Yellow River, the world's fifth longest river, watered some of the oldest farms on earth.

    {#blank#}1{#/blank#}Its source（源头）on Qinghai-Tibet Plateau is drying up. In most of the past 35 years, it didn't reach the sea.

    The Nile in Egypt, running 6, 650 km, is the longest river in the world.{#blank#}2{#/blank#}Now it is down to 2 billion m³ or so. Australia's Murray River reaches the sea only every other year. One fifth of America's Rio Grande has no water, either.

   {#blank#}3{#/blank#}

    Mostly it's damming（筑坝）and global warming that make rivers dry.{#blank#}4{#/blank#}Now about 45, 000 of them lie across the world's rivers. They hold back around 15% of the world's fresh water from running to the sea.

{#blank#}5{#/blank#}Warmer weather takes water away. The glacier（冰川）are becoming smaller. The source of the Yellow River is drying up because of it. Global warming has had certain effects on water sources. Droughts （干旱） happening around the world make people pay more attention to this fact.

    Are you bored with your mobile phone? Is it too heavy? Does it take too long to send and receive text message? If your answer is “Yes”, then read on!

EXIT introduces you to the latest mobile phone in town—the Speed Set 12000! It has over 30 features（特点）and weighs less than 130 grams! It is designed in Italy and made in India. It has a special gold button at the front that allows you to take pictures while you are talking. That's right, you can now talk and take pictures at the same time!

    The Speed Set 1200 is even more convenient to use than the Speed Set 1001. Like the Speed Set 1001, it has voice mail and caller show function, but the 1200 model has a bigger memory, so you can send and receive longer voice mails. Not only that, the newer model recognizes the voice mails, so it can tell you who the caller is. Also, the Speed Set 1200 has a more powerful battery, so you can recharge(充电) faster. With this model, it only takes you thirty minutes to recharge.

    The Speed Set 1200 has been already widely used in Asia and Europe. It is very popular with students and business people, as it has an Internet function that allows you to get information about news, sports and entertainment in just a few seconds.

    In the past, mobile phones were widely used to keep in touch with other people, but with the new Speed Set 1200, you can not only use it as a phone but also use it as a mini computer. So, if you are thinking of getting a new mobile phone, choose the Speed Set 1200. It's not just a phone. It's also a computer. At 2800 yuan, it's the cheaper mini computer in town!

    Have you ever heard of e-waste(electric waste,电子垃圾), which can be produced every day? How do you deal with your computers, MP4 players and mobile phones when they're broken or you want a new one?

    Most people just throw them away. With the development of electric industry, e-waste pollution has become a serious problem. According to the United Nations, in 2014, people around the world produced 41.8 million tons of e-waste and only recycled 6.5 million tons. The US was the biggest waster, producing 7.1 million tons. China came second, with 6 million tons.

    It's important to pay attention to e-waste. It can either be valuable or harmful（有害的）, depending on how we deal with it. E-waste is a valuable urban mine（城市矿藏）. The value of the metals, like gold and silver in the waste around the world, is amazing. And the metals can be reused. But if people throw them away, the toxic chemicals（有毒化学物质） can get into the earth or air,effectingthe environment and people's health.

    Apple, for example, now recycle people's used products in China when they are buying new ones. The company will test and repair the used ones and sell them at lower prices. To help reduce（减少）e-waste, we can also take computers and phones to see if companies offer recycling programs.

    If you look at the top of your phone, you'll usually see a lite symbol that says 3G or 4G. The "G" is the generation(代)" of your mobile network (移动网络). But these symbols will become things of the past after 5G networks fully arrive.

    On March 30, 2019, Shanghai vice mayor (副市长) Wu Qing made the first SG video call on a Huawei Mate x smartphone, CGTN reported. Shanghai has also become the first city in China to start testing 5G networks.

    About 100 times faster than 4G networks, 5G will let people download (下载) and upload data (数据) faster than ever before. But 5G won't just bring faster mobile internet. People can use it for many other things as well.

    For example, 5G will help to make self-driving cars safer. Today's self-driving test cars have one problem-lag (延迟). When the car "sees" an obstacle (障碍物), it sends this information to a data center and receives instructions (指令).

    However, it takes time to send and receive this information. With this kind of lag, the cars might hit each other because they don't receive instructions in time. With 5G, this lag will be greatly lowered (降低), making the cars safer, according to CNN. 5G could also be used to help the internet of things (IoT,物联网). IoT is a large online network that connects all things and people. Fast internet speed will be the key to developing this technology. The IoT could be used in a lot of ways. For example, with IoT, your refrigerator could automatically (自动地) place an order online for eggs when it finds that there are no eggs left inside.

Eating out is more popular in Britain today than it has ever been. It is reported that British people spend more eating out than cooking for themselves and eating at home. It seems that many British people are becoming more and more interested in how good their food tastes, and also how healthy it is.

However, eating out can also be expensive, so British people do not eat out every night. When having a date with friends, or having a birthday, many people like to go to a restaurant, and people often also eat in a restaurant before going to the cinema or the theater.

As in all cultures, there are many rules of manners about eating. The knife and fork should be used in the correct way. It is also impolite to speak with your mouth full then you are eating.
    Most British cities have a large collection of food as well as British food, from the very cheap to the very expensive—French, Italian, Indian, Chinese, Thai, Japanese and many, many more.

When people are too tired to cook after work, they often get a "takeaway". This means that they order from a take－out restaurant by telephone, and then go to get it. Many take-out restaurants also send it to your house. All you have to do is to open the door, pay and eat!