Imagine one day, the water taps in your house stop running. You have to buy water from shops. And still there {#blank#}1{#/blank#}water for everyone. Your mother has to save the family's shower water to do other things. Would you be able to stand that kind of life?

    Probably not. But that's what kids in Yemen are experiencing. Experts said Yemen is going to be the first country in the world to run out of water. {#blank#}2{#/blank#}a report, the capital, Sana'a, will run out of drinking water as early as 2025.

    Because of the shortage, the government often cuts the water supply. Hannan, an 18-year-old girl from Lahej, told the Times: "In a good week we'll have the water supply all week. But then the following week there will be water only for {#blank#}3{#/blank#}."

    Hannan said only rich people have enough water to use. They can buy water from the shops or from the water trucks. Private companies own the trucks. They {#blank#}4{#/blank#}every day to sell water—at very high prices. "A lot of people can't afford it," she said.

    The government is {#blank#}5{#/blank#}making use of seawater. But it will cost a lot and it may not happen soon enough to help the people of Yemen.

Why does the Sky Change Colours?

What is the sky? How high is it? What colour is it? What birds can live above it? These questions are difficult to answer, aren't they?

In fact, the sky has no colour. Then why does the sky look blue?

We know that there is air around the world. When planes fly, they need air to lift their wings (机翼). Planes can't fly very high. That's because the air gets thinner when they go higher. The same will happen to us if we go high enough. If we go up about 1,000 kilometres from the earth, we'll find no air there. Some birds can fly into the sky as high as a plane, but they cannot fly or live without air.

Looking up above us, you will see the blue sky with white clouds. It is usually light blue. The colour will be bluer when you see on the top of a high mountain. And you will see fewer clouds in the sky between you and the sun.

Sometimes the sky doesn't look blue. When the sun rises or falls, you will see red, orange, and other colours in the sky. Such are the most beautiful moments of the day.

Who can see the colours of the sky high above the earth? The astronauts! They can see those beautiful colours of the sky from outer space. However, before flying into outer space, they sit in a spaceship high above the earth, and there is no air at all. The sky will be that dark and its colour will be black.

Now you may understand that we see colours because the air scatters (使散射) the sunlight. Light travels through the air. Without air, there would be no light or colours.

Do you know that you are not outgoing enough? Do you want more friends, but are you too shy? Read the following rules. They will help you.

{#blank#}1{#/blank#} Always be clean. Shower, brush your teeth, and try to look nice. Dress in clothes that make you feel good and comfortable. Those make you feel more confident.

{#blank#}2{#/blank#} Try to smile more often at people. It will get them to think that you are friendly. Then they'll talk to you more even if they don't know you.

{#blank#}3{#/blank#} Some people worry about talking because they think, "What am I going to talk about with that person?" Outgoing people don't even think about it.  They just go up to people and say what they think.

{#blank#}4{#/blank#} You can't just talk. People will think that you're self-centered. You have to listen to others and give your opinions. Let them know you care.

{#blank#}5{#/blank#} Don't just stay at home and do nothing. Surf the net for news and information, and talk about it when you're with friends.

Some problems are difficult to solve in our life. However, there are a lot of number expressions （表达用语） that can help. Today, let me show you some examples. 

Sometimes we can "Kill two birds with one stone". That is to say, we can complete two goals （目标） with only one effort or action. But we must remember that "two wrongs don't make a right". If someone does something bad to you, you should not do the same to him. 

When I was a young child in school, my favourite subject was Maths. My teacher used to "give me three cheers" when I did well in Maths, praising （赞扬） my hard work and good grades. 

When I was in high school, some of my friends once had trouble doing their schoolwork. In fact, they did not care if they could finish high school. But it seemed that they really got a surprise when they completed their studies and graduated （毕业） from high school. They were "on cloud nine". 

"Nine times out of ten", students who do well in school often find good jobs. Some people work in an office doing the same things every day at nine-to-five jobs. However, it's good to know that happiness at work isn't just about money. 

A. DoubanFM: It might be the right music app for you. You can mark the songs you like. Those marked with a heart will be kept in another list as your favorites for you to enjoy anytime you want.

B. Balcizhan: This app tells you how many English words you need to learn every day. It can also be fun. The learning is like playing a guessing game. And you can practice remembering the new words in different ways.

C. Moment Camera: Many people like this app because of its frames (相框). The frames are beautiful in different styles. The photos are clear and the app is easy to use.

D. Qunar: You can find out lots of travel information from this app. It can not only present useful information about where you'd like to go but also help you save money during your trip.

E. China Daily: You can learn what happens around China every day from this app. It not only helps you know more about the country, but also helps you improve your English.

F. Amap: It can provide you with online map searching service. With the app, you can search for the  locations(位置) of streets, restaurants, banks, schools and so on.