1 . Let's take a minute to think about the water we use. The human body is 60% water and we need to drink lots of water to be healthy. When we are thirsty we just go to the kitchen and fill a glass with clean water.

    1    For example, farmers, who produce the food we eat, use water to make the plants grow. When we turn on a light or switch on a TV or a computer we use energy and we need water to produce this energy.

The truth is that we are lucky enough to have clean water whenever we want，but this is not the case for many people around the world.    2    That's around one in 10 people in the world. If we drink dirty water，we can catch diseases from the bacteria and become ill. Every year over 500，000 children die from diarrhea(腹泻)from dirty water. That's around 1，400 children every day！Also，in some countries children walk many kilometres every day to get water.    3    Therefore，they don't have time to learn how to read or write and don't get an education.

    4    On this day every year，countries around the world hold events to educate people about the problems of dirty water and that clean water is something that everyone should have around the world. At one school in the UK，children between the ages of 10 and 15 walk 6km with six litres of water.    5    People give them money to do this and all the money helps get clean water to as many people as possible around the world.

3 . The carbon footprint shows how much carbon dioxide a person emits(排放)in everyday life. It measures the amount offossil(化石)fuels and electricity someone uses up as well as the carbon footprint of the products they buy. When we use our cars or heat our homes with carbon dioxide，various other gases are set free.     1    

You can measure your carbon footprint by using a calculator that you can find on various websites.     2     In America for example，every citizen produces about 28 tons of carbon dioxide and other dangerous gases a year；in Great Britain the amount is about 10 tons.

    3     The way we travel，for example，has a major effect on our environment. Use your bike or walk for short distances. Public transport is a way of getting to places without putting a burden on the environment.     4     Many environmental experts，however，argue that it often saves energy to buy food that is produced naturally in faraway places than consuming food grown locally in greenhouses. In your home you can contribute to saving energy by turning off lights if you don’t need them or by avoiding the use of air conditioners. Recycling plastic glass and paper can also reduce your carbon footprint dramatically.

    5     Only if we concentrate on reducing carbon emissions together can we hope to make our environment better.

5 . Are you facing a situation that looks impossible to fix?

In 1969,the pollution was terrible along the Cuyahoga River Cleveland, Ohio. It    1    (be) unimaginable that it could ever be cleaned up. The river was so polluted that it    2    (actual) caught fire and burned. Now, years later, this river is one of    3    most outstanding（杰出的）examples of environmental cleanup.

But the river wasn’t changed in a few days    4    even a few months. It took years of work     5    (reduce) the industrial pollution and clean the water. Finally, that hard work paid off and now the water in the river is    6    (clean) than ever.

Maybe you are facing an impossible situation. Maybe you have a habit    7    is driving your family crazy. Possibly you drink too much or don’t know how to control your credit card use. When you face such an impossible situation, don’t you want a quick fix and something to change immediately?

While there are    8    (amaze) stories of instant transformation, for most of us the    9    (change) are gradual and require a lot of effort and work, like cleaning up a polluted river. Just be     10    (patience).

Earth Day     1     (found) in 1970 as a day of education about environmental problems, and Earth Day 20 occurs on Wednesday, April 22—the holiday’s 50th anniversary. The holiday is now a global celebration that’s sometimes extended into Earth Week, a full seven days of     2     (event) focused on green living.

    3     (elect) to the U.S. Senate（参议院）in 1962, Senator Gaylord Nelson was determined to convince the federal government that the planet was     4     risk. In 1969, Nelson developed the idea for Earth Day after     5     (inspire) by the anti-Vietnam War “teach-ins” that were taking place on college campuses around the United States.

Denis Hayes, a young activist     6     had served as student president at Stanford University, was selected as Earth Day’s national coordinator（协调者）, and he worked with     7     army of student volunteers and several staff members from Nelson’s Senate office     8     (organize) the project.

The first Earth Day was effective at raising     9     (aware) about environmental problems and transforming public attitudes. Earth Day kicked off the “Environmental decade with a bang,” as Senator Nelson later put it. The theme of Earth Day 2020 is “climate action.” EarthDay.org hopes it will be the     10     (large) volunteer event in history.

7 . Earth Hour is organized by the World Wide Fund for Nature. It's a big event usually at the end of March every year. On this evening, people “go dark”.     1    

It's true that turning off lights for just one hour saves only a small amount of power.    2    On one level, joining in Earth Hour makes people think about the problem of climate change and what we can do in everyday life to protect nature.

But on another level, a large number of people’s acting together sends a powerful message to governments and companies.     3     They begin considering green issues when big decisions.

The logo(标识) of Earth Hour is “60+” .The number 60 is for the 60 minutes of Earth Hour.     4     In fact, people who join in Earth Hour say that taking part makes them want to do more for the environment.

    5     Musicians give concerts by playing acoustic(原声的) instruments instead of electric ones, and using candles instead of electric lights. Celebrity chefs have created special recipes for families to prepare and eat by candlelight. Tree-planting sessions, group walks and runs are also among the options.

8 . The scientists who re-engineered the plastic-eating enzyme(酶) PETase have now created a new enzyme called “cocktail” , which can digest plastic up to six times faster.

PETase breaks down PET back into its building blocks, creating an opportunity to recycle plastic and reduce plastic pollution. PET is the most common thermoplastic(热塑性塑料) used to make single-use drinks bottles, which takes hundreds of years to break down in the environment, but PETase can shorten this time to days. The initial discovery set up the prospect of a revolution in plastic recycling, creating a potential low-energy solution to tackle plastic waste.

Now, the same trans-Atlantic team have combined PETase and its “partner”, a second enzyme called MHETase, to generate much bigger improvements: simply mixing PETase with MHETase doubled the speed of PET breakdown, and engineering a connection between the two enzymes to create a “super-enzyme”, increased this activity by a further three times.

The team was co-led by the scientists who engineered PETase, Professor John McGeehan and Dr Gregg Beckham. Professor McGeehan said: “Gregg and I were chatting about how PETase attacks the surface of the plastics and MHETase chops things up further, so it seemed natural to see if we could use them together. Our first experiments showed that they did work better together, so we decided to physically link them. It took a great deal of work, but it was worth the effort — we were delighted to see that our new enzyme is up to three times faster than the separate enzymes.”

The original PETase enzyme discovery indicated the first hope that a solution to the global plastic pollution problem might be within grasp, though PETase alone is not yet fast enough to handle the tons of PET bottles. Combining it with a second enzyme, and finding together they work even faster, means another leap forward has been taken towards finding a solution to plastic waste. PETase and the new combined MHETase-PETase both work by digesting PET plastic. This allows for plastics to be made and reused endlessly, reducing our reliance on fossil(化石) resources.

9 . How to Reduce Gift Wrap Waste

Wrapping paper may have “paper” in its name, but that doesn’t automatically mean it can be recycled.     1     Try these suggestions for cutting down the amount of wrapping paper you throw away.

Reuse what you have.     2     It’s estimated that the U.S. produces 4.6 million pounds of wrapping paper annually, and 2.3 million pounds of that stays in people’s homes, awaiting reuse.

Use different materials.     3     Select basic brown thick paper that can be made up with a bow, ribbons, leaves, pinecones or markers. Repurpose newspapers, old posters and children’s school artworks as wrapping paper. There are plenty of other eco-friendly alternatives to wrapping paper that are just delightful and celebratory.

    4     Use baskets, fabric, gift boxes or bags, tea towels, and more to contain and display your presents. Learn the Japanese art of wrapping, using beautiful knots(绳结) to fasten colorful, reusable fabrics in attractive ways. This way, you’ll have no wrapping paper waste to deal with.

Ask for better paper. Shops store what customers want, and recyclability should be a top priority, so let that be known when you’re out shopping. As explained by Simon Ellin, CEO of the Recycling Association, a trade body that represents about 90 waste management companies and paper merchants in the United Kingdom, “It’s a campaign we’ve been on all year — do you really need to design a non-paper wrapping paper? Make paper with recycling in mind!”     5    

10 . Climate change leads to a threat to the world’s sandy beaches, and as many as half of them could disappear by 2100, a new study has found. Even by 2050 some coastlines could be unrecognizable from what we see today, with 10% to 12% facing severe erosion (侵蚀).

Using updated sea level rise predictions, the researchers analyzed how beaches around the world would be in a future with higher seas and more damaging storms. They also considered natural processes like wave erosion, as well as human factors-like coastal building developments, all of which can affect a beach’s health. The study found that sea level rise is expected to outweigh these other factors, and that the more heat-trapping gases humans put into the atmosphere, the worse the influences on the world’s beaches are likely to be.

It’s hard to overstate just how important the world’s beaches are. They cover more than one third of the world’s coastlines, and protect coastal areas from storms. Beaches are also important economic engines, supporting relaxation, tourism and other activities. And in some areas, the beach is more than a vacation destination. In places like Australia, life near the coast revolves around the beach for much of the year.

Some of the world’s most popular beaches are already taking action. Places like Miami Beach are trucking in thousands of tons of sand to patch up (修复) badly eroded shorelines, while others have built sea walls and breakwaters in an attempt to hold precious sand in place. But the financial and environmental costs of these projects are huge, and scientists say rising seas and more powerful storms, supercharged by a warmer climate, will make this a losing battle.

However, the researchers did find that humans have some control over what happens to the world’s beaches. If the world’s governments are able to stick to modest cuts to heat-trapping gas pollution, the researchers found that 22%of projected beach losses by 2050 could be prevented, a number that grows to 40%by 2100 if greenhouse gases are limited.