In late August, 2005, Hurricane Katrina, one of the most     1     （destroy) hurricanes in American history, hit the south-eastern parts of the country.

It began on August 23, causing only slight damage in the beginning. But it soon     2     (grow) to be a Category 5 hurricane over the warm waters of the Gulf of Mexico, causing severe damage along its path.

New Orleans, a city     3     was built largely below sea level, was worst hit. In     4     (react) to the coming hurricane, the city government gave an order     5    (clear) the city of all residents. However, many stayed in the city. Some of them chose to stay because they believed that the city’s defense system     6     (keep) them safe and sound, while others were unable to leave     7     they had no access to transport. The defense system finally failed. As     8     result, 80% the city was flooded for weeks. People were stuck in the city without power, food, or drinking water,     9     (anxious) waiting for rescue.

The hurricane died away on August 31. In all, Hurricane Katrina caused nearly 2, 000 deaths, and left     10     (million) of people homeless.

3 . The wish to capture the wonder of nature on a smartphone or camera is understandable. People like the beauty of nature and also want to share with their followers, friends and family, but our relationship with the outdoors should not be centered around social media. The “do it for the ‘gram’” thought needs to be reconsidered.

Social media has undoubtedly helped attract more visitors to wild places. There are both good and bad sides that come with an increased visitation to these sites. Visiting nature and observing wildlife can help people feel more connected to wild plants and animals. These experiences may encourage more protection of natural spaces. Yet increased traffic to these sites has also caused them harm. Spaces that are ill-equipped to deal with too many visits experience environmental degradation, which in turn can endanger those who take photos by putting them in dangerous situations. Search and rescue cases have increased by 38% in the last few years in LA County, some of which were connected to adventurers trying to capture photos for their social media. Deadly falls in the outdoors can and should be avoided with less photographing for social media.

Recently, one highly visited natural site stopped photography-only tours. Antelope Canyon in Page, Arizona, will no longer be allowing visits that are centered around cameras. Handheld phones will still be allowed, but large tripods(三角架) and monopods(独脚架) will not be. This is a great first step that should be brought to other natural settings, especially in places that have already been completely photographed by professionals.

It is necessary to free ourselves from technology every once and a while. The unhealthy attachment to photography and social media feeds has created problems for humans and nature, and should be replaced with practicing mindfulness while in the outdoors.

7 . It is projected that by the year 2050, the urban population in the world will increase by 2.5 billion. The big question is not how many people can reside in an urban area, but how we can build sustainable and livable cities.     1    

Reducing transport emissions is the first step towards sustainable development. A safe and reliable transport system is fundamental to economic growth. However, the fuel driven cars and other petroleum-dependent means of transportation are quite alarming. They are a major source of carbon dioxide emissions.     2     In a sustainable city model, the use of zero-emission electric vehicles is practicable. Besides, encouraging people to walk or cycle around the city is also a reasonable sustainable development model.

    3     Parks and gardens go a long way in making a city livable and residents can get a green place to relax and walk freely. In the big cities, more green spaces are being set aside for recreational purposes.     4     These green spaces, forming a mini forest, can reduce air pollution and CO₂ emissions and enhance air quality.

Improving the sewer system(排水系统) is also important to clean up our environment.     5     One reason is that streets, buildings and sidewalks are waterproof. So the rainwater only flows on the surface. As a way to deal with and adapt to urban flooding, sewer systems and stormwater networks should be improved. This is much more urgent and practical. Because the old infrastructure cannot serve the new paradigm of rapid environmental change.