The Xi’an City Wall is the most complete city wall that has survived China’s long history. It     1     (build) originally to protect the city     2     the Tang dynasty and has now been completely restored (修复). It is possible       3     (walk) or bike the entire 14 kilometers.

We accessed the wall through the South Gate. The wall is 12 meters high and from here you can see streams of people moving inside and outside the City Wall.

After     4     (spend) some time looking at all the defensive equipment at the wall, we decided it was time for some action and what     5     (good) than to ride on a piece of history!

We     6     (hire) our bikes from the rental place at the South Gate. My bike was old and shaky     7     did the job. It took us about 3 hours to go all     8     way around the Xi’an City Wall. Supposedly you can do it in two hours, but we stopped at the different gates and     9     (watchtower) to take pictures or just to watch the local people going about their     10     (day) routines.

Kim Cobb, a professor at the Georgia Institute of Technology in Atlanta, is one of a small but growing minority of academics     1     are cutting back on their air travel because of climate change. Travelling to conferences, lectures, workshops, and the like frequently by plane       2    （view） as important for scientists to get together and exchange information. But Cobb and others     3     （be） now questioning that idea pushing conferences to provide more chances to participate remotely, and     4    （change） their personal behavior to do their part in dealing with the climate change crisis. On a website called No Fly Climate Sci, for example,     5    （rough） 200 academics - many of them climate scientists     6     （promise） to fly as little as possible since the effort started two years ago.

Cobb, for her part, started to ask conference organizers who invited her to speak     7     she could do so remotely; about three-quarters of     8     time, they agreed. When the answer, was no, she, declined the     9     （invite）. That approach brought Cobb's air travel last year down by 75%, and she plans     10    （continue） the practice. "It has been fairly rewarding. ", she says, "a really positive change."

The shelves in most supermarkets are full of family-size this and multi-buy that. However, if you’re shopping for one, buying extra     1     (benefit) from price reductions doesn’t make sense. Either your shopping is then too heavy to carry home     2     you can’t use what you’ve bought while it’s still fresh.

Of course, shops are not charities — they price goods in the way     3     will make them the most money. If most of their customers are happy to buy larger quantities, that’s     4     they’ll promote. But that leaves the solo (单独) customers out of pocket and disappointed.

Many supermarkets are no longer doing “buy one get one free” promotions because of the     5     (criticize) that they lead to waste. Consumers prefer money off individual items. However, though it’s nice to get a few cents off a pack of sausages, it would help even more if they could sometimes     6     (offer) in smaller packs. Even the biggest sausage fan doesn’t want to eat them every day.

If your supermarket sells loose produce, then buying smaller quantities is easier. Over the last two years, some supermarkets     7     (start) selling chicken or salad in packs     8     (design) with two halves containing separate portions (份). Then, when you use one section,     9     other stays fresh.

Who knows, perhaps some of the more forward-looking     10     (one) may yet come out with a whole range of “just for you” pack sizes with special offers as well.

I've always loved the ocean. In the    1     (seven) grade,I started volunteering at the Monterey Bay Aquarium in California. I was upset to learn that many sea animals eat plastic garbage,     2     (think)it is food.

I decided to do something     3     (educate) people about this problem. I held presentations at schools to teach kids about plastic waste. I wanted to reach businesses too. I decided that if I learned of a company    4     used a lot of plastic, I'd send it an email urging it to cut back.

One day, I saw a commercial for a health-care company. People in the ad were using plastic straws （吸管）.   I found the contact information of the company    5     emailed its president. I told him how     6     (harm) plastic could be to the environment and asked him to consider using more eco-friendly options. I was so    7     (excite) when he wrote back to me.He said he would make sure that the company cut its use of plastic straws in half.

I kept going. Whenever I heard of businesses using plastic, I'd send an email. One of the biggest companies I wrote to     8     (be) Alaska Airlines Paris. A company     9     (represent) wrote back and told me the airline was switching over     10     plastic to paper cups on all of its 1,200 daily flights.

Heatherwick Studio recently built a greenhouse at the edge of the National Trust’s Woolbeding Gardens. This beautiful structure, named Glasshouse, is at the centre of a new garden that shows how the Silk Road influences English gardens even in modern times.

The latest     1     (engineer) techniques are applied to create this protective     2     (function) structure that is also beautiful. The design features ten steel “sepals (萼片)” made of glass and aluminium (铝). These sepals open on warm days     3     (give) the inside plants sunshine and fresh air. In cold weather, the structure stays     4     (close) to protect the plants.

Further, the Silk Route Garden around the greenhouse     5     (walk) visitors through a journey influenced by the ancient Silk Road, by which silk as well as many plant species came to Britain for     6     first time. These plants included modern Western     7     (favourite) such as rosemary, lavender and fennel. The garden also contains a winding path that guides visitors through the twelve regions of the Silk Road. The path offers over 300 plant species for visitors to see, too.

The Glasshouse stands     8     a great achievement in contemporary design, to house the plants of the southwestern part of China at the end of a path retracing (追溯) the steps along the Silk Route     9     brought the plants from their native habitat in Asia to come to define much of the     10     (rich) of gardening in England.

Nina has run marathons in 32 countries. All of her runs have a guiding purpose: to call attention     1     global water issues. Nina recently finished her year-long series of runs in Chicago,     2     thousands were attending a water conference.She called for action     3    (address)the struggles of people around the world     4    (face) “too little water or too dirty water”. Her efforts have encouraged others to take part by running through a global campaign called“Run Blue”.