What is the sky? How high is it? What color is it? What birds can live above it? These questions are difficult to answer, aren't they? In fact, the sky has no color. 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. Planes can't fly very high. That is 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 1,200 kilometers 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 color would 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 and falls, you will see red, orange and other colors in the sky, such are the most beautiful moments of the day.

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

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

    Cars make our lives more convenient. But they can also be a problem. For example, fossil fuel (化石燃料) cars mainly cause air pollution.

    To improve the environment, many countries are developing electric vehicles (EVs,电动车). Among them, China is taking a leading role and has created the world's largest EV market.

    Last year, over 40 per cent of the 753,000 EVs sold in the world were sold in China, more than twice as many as the number sold in the United States.

    "Filling up a fossil fuel car with gas (汽油) is more expensive than charging (充电) an electric car," said Wu Hao, who bought an electric car this year.

    However, there are still some problems. It can be hard to find charging piles (充电桩) and the cars can't go far before being recharged.

    Some of these problems are being solved. In 2014, China had 31,000 charging piles. Now China has the world's largest EV charging network, with more than 450,000 charging piles in total.

    Developing EVs is one of many efforts that China has made to cut down pressure on its environment after the government promised to stop increases in carbon dioxide emissions (二氧化碳排放量) by 2030.

    "As China goes, so will the world's car industry," the Wall Street Journal said.

    We are lucky to live in a rich country where we have many things. However, most of us usually {#blank#}1{#/blank#} (waste) some things.

    Electricity is one thing that we waste most. Lights, TVs, {#blank#}2{#/blank#} (radio) and other things are often kept on even when no one is using them. We should turn them off {#blank#}3{#/blank#} we do not need them. It takes  {#blank#}4{#/blank#} (little) than a second to do it. Anyhow, not wasting electricity saves money, because we do not have to pay for the electricity we do not use. The {#blank#}5{#/blank#} (two) thing that we often waste is water. Fresh water is precious, so it shouldn't be wasted. It is only a simple matter of turning {#blank#}6{#/blank#}a tap. I am sure everybody can do this {#blank#}7{#/blank#} (easy) if he wants to. Another big waste is food. My mother used to cook so much food that much of it was thrown away. I told her we had wasted so much {#blank#}8{#/blank#} (food). She thought I was right and now cooks mainly what we can eat.

    It is not right to be wasteful. I find there is a simple way of not wasting things. That is {#blank#}9{#/blank#} (use) only what we need. Do not touch what we do not need. {#blank#}10{#/blank#}this way, we can stop being wasteful.

    How to build good relationships with people from other cultures? Actually, it is important to learn some communication skill. {#blank#}1{#/blank#}.

    Learn about the culture in advance. A little knowledge can go a long way. So if you have time before going abroad or meeting with someone from another culture, try to take time to learn the basic "do's and don'ts" of that culture. {#blank#}2{#/blank#} It's very convenient.

    Be respectful and tolerant. {#blank#}3{#/blank#} Signs of these may appear when you communicate with people from other cultures. However, it is not the time to judge people based on these differences during basic communication. Instead, respect them for what they are, and tolerate them.

    Speak clearly and slowly. But do not shout at others even if they don't understand you. {#blank#}4{#/blank#} Instead, it can be seen as a rude behavior. What's more, even if there are difficulties in communicating with people from other cultures, do not treat other people as though they are stupid.

    {#blank#}5{#/blank#} In some cultures, looking another person in the eye when you speak is seen as a sign of honesty and interest. However, in other cultures, it may be disrespectful.

    Parents, especially those of teenagers, care about their children's education more than anything else. They would do    {#blank#}1{#/blank#} for their children. Many of them spend most of their spare time {#blank#}2{#/blank#} their children with their studies. If they have no time or cannot do it themselves, they would hire family teachers {#blank#}3{#/blank#} send their children to after-class schools. It seems as if a better education is all that parents expect for {#blank#}4{#/blank#}.

    How can we explain the present situation? First of all, many parents have {#blank#}5{#/blank#} that future success depends more and more {#blank#}6{#/blank#} skills and education. Secondly, in a competitive(竞争的) society there are both losers and {#blank#}7{#/blank#}. Those who have better skills and more knowledge will enjoy {#blank#}8{#/blank#} opportunities(机会).

    Certainly, it is important to learn to succeed, but the {#blank#}9{#/blank#} thing to learn is how to survive(生存) and how to be a qualified citizen(合格的公民). {#blank#}10{#/blank#} this is included a good education, the children will surely have a bright future and he healthy in body and mind.