Tibetan antelopes live on the plains of Tibet, Xinjiang and Qinghai. Watching them move slowly     1     the green grass, I’m     2    (strike) by their beauty and also reminded of the danger they were in. They were hunted     3    (legal) for their     4    (value) fur.

Economic development is necessary if we want to improve society. There comes     5     time when the old must give way     6     the new and it is not possible     7    (preserve) everything from our past as we move towards the future. Finding and     8    (keep) the right balance between progress and the protection of cultural sites can be a big challenge. Big challenges, however, can sometimes lead to great     9    (solve).

By     10     (share) so many digital photos over the Internet, the group hopes to promote even     11     (wide) interest around the world in China’s ancient history, culture and traditions. They also hope to     12    (far) educate people about the importance of safeguarding historic and cultural relics for future generations to understand and appreciate.     13     one researcher who is working on the project explains, “Appreciating one’s own cultural heritage is very important for understanding     14    (one). Appreciating the cultural heritage of other countries is very important for international     15    (communicate) and understanding.”

4 . Going vegan or vegetarian is one way to decrease your diet’s impact on greenhouse gas emissions (排放) — but it isn’t the only way. A recent Purdue University study suggests that smaller changes can make a difference too, while improving your health.

After analyzing the 2010 grocery purchases of more than 57,000 U.S. families, Purdue researchers found 71 percent could reduce their food carbon footprint by making some changes. One is to skip the unhealthy snacks. Avoiding foods with high calorie is important and low nutritional value can reduce the total carbon footprint of U.S. family food consumption by nearly 10 percent. Items like candy, soda, and packaged snacks take more ingredients and more processing, which translates to higher environmental impacts.

Another effective way to reduce your carbon emissions is to avoid bulk buys. Households of one or two people may end up with food waste when they try to save money with bulk buys. Before you buy supersize, consider whether a three-pound jar of peanut butter will go bad before it’s used up.

The researchers of the study also suggest consuming fewer ready-made foods. One average microwave meal may not have a very large carbon footprint. But buying them regularly can add up to high emissions because ready-made foods are sold in large quantities, which makes their carbon footprint significant, the study found.

By making the above changes, the U.S. could cut more than a quarter of emissions from household food consumption, the researchers say. That’s about 36 million metric tons — about what 6.6 million households generate in a year of electricity use. “Collective action can make a huge impact,” says study co-author Hua Cai.

Litter is everywhere, doing great harm to the environment and life on our planet. Jeff Kirschner, who wants to build a litter-free world, started a     1     (globe) community named Litterati     2     (settle) this problem.

The story began with his 6-year-old daughter. One day they were going on a hike     3     the girl noticed a broken plastic tub (浴盆) in a river. She said, “Daddy, that doesn`t go there.” That took Kirschner     4     surprise. He, like many adults, had become so used to seeing the rubbish     5     (throw) around them that he hadn’t given it     6     second look. What his daughter said reminded him of the serious problem our planet faced.

Jeff started to take     7     (act). He created Litterati, an app that makes it fun to pick up litter. The idea is     8     (fair) simple: Spot a piece of trash, take a photo, post the photo online and then put the litter into dustbins.

    9     (see) that Jeff was keeping a record of the positive impact he was having on the planet, people worldwide started participating. Up to now, over 2,500,000 photos posted by 3,500 people from over 40 countries     10     (find) their way to Litterati`s digital landfill.

6 . My husband and I always wanted to go to the Caribbean but didn’t know much about the islands or how we were going to afford it. By chance, a friend of ours in Australia mentioned “pet sitting” and that it is something you can do all over the world.

We quickly created an account on a pet sitting website and began searching for options. There were only a couple of sits available in that part of the world, but we tried our luck, sent a request, and to our surprise, landed a three-month job in Grenada, so our year was going to be taken up with Caribbean pet sits.

Inspired by a Canadian couple, we decided to start our own travel blog. We began by writing about The British Virgin Islands, highlighting the beautiful beaches. However, for every photo album of a beautiful beach, there were 10 photos of trash (垃圾). It was hard to ignore the plastic pollution issue, especially on such primitive and remote beaches. So, we began to share photos of the trash we saw and how much we could pick upon our daily dog walks.

The more we looked into plastic pollution, the more we realized the severity of the global plastic pollution. From that point, we used our platform to create awareness and highlight ways to say no to plastic and travel plastic-free. We changed our daily routines, our way of living, and even our diets to accommodate more organic foods and little to no plastic packaging.

It’s been over three years now and we continue to do what we can. This journey has led us to some amazing places, working with great brands and even organizing a country-wide beach clean-up campaign in Grenada.

Our aim now is to keep on going. We love connecting with like-minded people. It’s been amazing few years that was sparked by a conversation about pet sitting. Who would have guessed?

Continued greenhouse gas emissions will result in further warming and long-lasting changes to the global climate. This requires the attention of people all over the world. Governments need to consider     1    and taking appropriate actions and measures to reduce greenhouse gas emissions. We as individuals can also reduce our “carbon footprint” by     2    the amount of carbon dioxide our lifestyles produce. It is our responsibility     3    every opportunity to educate everyone about global warming, along with its causes and impacts, because this is the most serious issue affecting all of us on this planet. So what will you do to help?

    4    , the local authorities began to use the media to spread environmental     5    and encourage greater use of clean energy. At the same time, they started to carry out     6    regularly and fine tourist organisations for abuses.     7    these measures, it is believed that the beauty of the Li River will be preserved for generations     8    

8 . The Antarctic’s snow-white environment is going green and facing other unexpected threats.

Scientists say that as temperatures go up in the polar areas, invading(侵袭)plants and insects, including the flies, cause a major threat.

More and more of these invaders, in the form of larvae(幼虫)or seeds, are surviving in coastal areas around the South Pole, where the temperature has risen by almost 3℃ over the past five decades. Glaciers have melted, exposing more land which has been occupied by mosses that have been found to be growing more quickly and thickly than ever before—providing potential green homes for invaders.

“The common houseflies are a perfect example of the problem the Antarctic now faces from invading species,” said Dominic Hodgson of the British Antarctic Survey. “They arrive by ship, where they exist in kitchens. They now have an increasing chance of surviving in the Antarctic as it warms up, and that is a worry. Insects like the houseflies carry bacteria that could have a deadly effect on native life forms.”

The Antarctic has several native species of insects. Together with its native mosses, these are now under increased threat from three major sources: visiting scientists, increasing number of tourists and global warming. However, it is global warming that is the main driver of the “greening” of the Antarctic.

In the 2015-2016 travel season, more than 38,000 tourists visited the Antarctic. “These tourists are often very careful about not leaving waste. But they could carry seeds or larvae on their boots when they set foot on the Antarctic,” said Dominic.

More and more invading insects and plants have been found on the Antarctic and have required removal. “The insects and plants that are native to the Antarctic have survived there for thousands of years,” said Dominic. “We have to act now if we want to save the environment.”