March 22nd is World Water Day. It started in 1993. It not only makes us think about the importance of water, but also calls on (号召) us to 1 and protect water. Today, we're facing terrible water problems. Among them, wastewater problem is especially2. And the subject of World Water Day in 2017 is “wastewater”.

    What is wastewater? It is used water. Usually, wastewater comes from homes, 3, hospitals and so on. It is produced by different kinds of activities, including washing the machines, taking showers and using the kitchen. The rain also 4 wastewater when it is running down the street during a storm. No matter where it comes from, this kind of water is sure to have5harmful in it.

    6must we treat (处理) wastewater? Wastewater has a big influence on our life. It causes both illness for us and pollution for the environment. We must care for our environment and our own7.

    How can we treat wastewater? Different kinds of wastewater need different ways of treatment. Wastewater 8 homes can be reused. Then there will be 9 wastewater. Also, factory wastewater has to be cleaned 10 it goes back to nature.

    Many people say that they have seen flying saucers（飞碟） in the sky. 1 can these things be?

    Some people think that they are spaceships from other planets. Doctors 2 that perhaps they are only a weakness of the eyes. It is possible that they are our own planes 3 very high. Or are they birds with the sun's light on them?

    But some people say that they have seen them 4. They have seen beings（人） get off them and walk around. They have 5 to those beings, sometimes in English. People have 6 photos of flying saucers and of these beings. We have seen the photos, but sometimes the people had to take them in a 7. Children have seen flying saucers, and even dogs have seen them. Perhaps we do not think that the 8 of children, or dogs are important. But school-teachers have 9 seen them and Air Force officers and 10 policemen. Must we not listen to these people?

Mobike—it's a bike showing network where users search for a ride through an App. Mobike 1in shanghai at the end of last year.2 December 2016, Shanghai became 3 bike- share city in the world. And then Mobike recently expanded to Beijing, Guangzhou and Shenzhen. They are becoming 4 popular, especially among white -collar workers during rush hours. For that reason, a large number of bikes5in the streets. The bike ride's record has reached about twenty6on a single day .

    Mobike is7convenient that the users can find and leave bikes wherever they'd like. The users8 have the company's mobile's APP just need to use their phones 9 the QR code (二维码) on the bike, and then unlock the bike to begin the timer on the Uber-esque .Besides Mobike doesn't use a parking station in the street.Instead, users can10bikes anywhere with the app-controlled smart lock.11 it also means that users sometimes leave them in a bad place where it's hard for12users to find them. To deal with this problem, the founder of Mobike and her team 13on a points-based system to punish unruly rides.

    Sharing  bikes is made to reduce the pressure of traffic.14 it can run well, and the price is kept low, it may be a great15 to protect the environment .

    We are lucky to live in a rich country where we have many things. However, most of us usually 1some things.

    Electricity(电) is one thing that we waste 2. Lights, TVs,3 and other things are often kept on even when no one is using them. We should turn them off when we do not need them. It 4less than a second to do it. Anyhow, not wasting electricity is saving money, because we do not have to 5the electricity we do not use.

    The second thing that we often waste is water. Fresh water is precious(宝贵的)，6 it shouldn't be wasted. It is only a simple matter of turning off a tap. I am sure7can do this easily if he wants to.

    8big waste is food. My mother 9cook so much food that much of it was thrown away. I told her we had wasted so much 10. She thought I was right and now 11cooks what we can eat.

    It is not12to be wasteful. I find there is a simple 13of not wasting things. That is to use only what we14. Do not touch what we do not need.15 this way we can stop being wasteful.

    Living on Earth is like living in a terrarium (玻璃容器). All the water on 1 has always been here. The water never goes away and new water is never created. You might say the water is 2. Yes. Water changes its form as it moves through the 3 cycle, from liquid (液体) to solid, then to gas. The cycle happens all over again and again. The water cycle 4 to purify (净化) the water. However, once the soil and air are polluted, it is harder for the water to get clean.

    More than 70％ of the human body is water. Next to oxygen, water is the most 5 part of our life. We drink water. We bathe and shower in water. Each person 6 about 70 gallons of water each day.

    Out of all the water on Earth only 1％ is flesh water. We can all help protect water by doing things like 7 the tap when we brush our teeth.

    Water can get polluted by many different things. Sometimes it 8 when people are careless with the chemicals. Every year thousands of people get sick from 9 water. So everyone must work together to 10 water clean. Our lives depend on it!

    Hainan Airlines Flight 497 took off from Beijing at 14: 15 on Tuesday, November 21st 2017, and headed to Chicago. The airplane 1 with biological aviation fuel (生物航空燃料). They are 2 waste cooking oil. And this is the first China-US flight to 3 green aviation fuel. The flight will arrive at Chicago O'Hare International Airport at 12: 55 local 4 on Tuesday. It will fly 11, 297 kilometers on the 5.

    The fuel made from restaurants waste kitchen oil 6 Zhenhai Refining and Chemical Company. This company 7 in Ningbo, East China's Zhejiang Province. It's a subsidiary (子公司) of China Petroleum and Chemical Corp.

    Sinopec said this kind of fuel from restaurants waste kitchen oil will help to reduce car-bon dioxide in the 8. And it is a new way to make use of waste. Sinopec spokesman Lyu Dapeng said this aviation fuel has 9 safety standards (标准). And Sinopec hopes it can be 10 used in 2018. In March 2015, Hainan Airlines once made the first home flight with bio-logical aviation fuel on a Boeing 737.