2 . For more than 100 million years sea turtles (海龟) have covered huge distances across the world’s oceans, making them among the oldest creatures on the planet. However, they are on the list of endangered species.

Different from some animals like snakes, the sex of the baby sea turtles, called hatchlings , is determined by the environment after fertilization (受精). The temperature of the eggs during a certain period of development is the deciding factor in determining sex, and small changes in temperature can cause very big changes in the sex ratio (比例). Often, eggs at low temperatures (22—27℃) produce males, while eggs at higher temperatures (30℃ and above) produce females. At temperatures in 29℃, which is good for a balanced sex ratio of turtle hatchlings. If temperature reaches 36℃, no hatchlings will be produced.

Climate change has a powerful effect on turtle nesting (筑巢) sites. It changes sand temperatures, which then affects the sex of the hatchlings. Scientists have found that unusually warm temperatures caused by climate change are upsetting the normal ratios, resulting in fewer male hatchlings. The past four hottest summers in Florida have seen only female sea turtles. And an Australian study has shown a similar effect in which 99% of the hatchlings are female.

In addition to rising temperatures, turtles are also facing the threat of too much plastic in the oceans, along with a number of other threats. “Plastic pollution is a problem for turtles as they can mistake plastics for food easily. Even a single piece of plastic can kill a turtle,” Dr Couper, working at the Queensland Museum, said. “We have collected some plastics taken from turtles’ stomachs to show people what kinds of things are showing up on beaches. I want it to be an eye opener.”

3 . Many animals and plants are endangered in the world today. These endangered species are threatened with becoming extinct, meaning they will no longer exist on Earth. Examples include the Cuban Macaw and the Sri Lankan Legume Tree. Illegal hunting, and collecting of the Macaw bird for pets, led to its extinction. While the main reason the native Sri Lankan Legume Tree went extinct was due to habitat loss from development in the 20th century. The main cause for animals and plants disappearing is often a damage to the food chain due to hunting, habitat loss or even the introduction of new species.

Every living thing from one- celled animals to a blue whale needs to eat. Nature is connected and controlled by many weak food chains. A food chain describes who eats whom in a habitat. When one of the links in a food chain is no longer present—for example, a species goes extinct—the food chain breaks and sometimes this can cause other animals to disappear and the whole system can become imbalanced or even collapsed.

Humans can have horrible effects on food chains. When people first explored the world, they took animal and plant species from their home countries to the places they explored and settled in. They did not realize the consequences of introducing invasive species. By doing so, they were damaging the natural food chains of the areas they explored.

Nowadays there are strict rules controlling the movement of animals and plants between countries. But some parts of the world are still experiencing problems with invasive species introduced hundreds of years ago.

With rising awareness of how we affect the natural environment, hopefully we can learn to protect these food chains and help them to thrive. Otherwise the continued loss of species will eventually mean our own extinction.

4 . Corals are comeback creatures. As the world froze and melted and sea levels rose and fell over 30,000 years, Australia’s Great Barrier Reef, which is roughly the size of Italy, died and revived five times. But now, due to human activities, corals face the most complex condition they have yet had to deal with.

According to the Intergovernmental Panel on Climate change, a rise in global temperatures of 1.5℃ could cause coral reefs to decline 70-90%. The planet is about 1℃ hotter than in the 19th century and its seas are becoming warmer, stormier and more acidic (酸性的). This is already affecting relations between corals and the single-celled algae (海藻), which give them their color. When waters become unusually warm, algae float away, leaving reefs a ghostly white. This “bleaching” is happening five times as often as it did in the 1970s. Meanwhile the changing chemistry of the oceans makes it harder for corals to form their structures.

If corals go, divers and marine biologists are not the only people who will miss them. Reefs take up only a percent of the sea floor, but support a quarter of the planet’s fish diversity. The fish that reefs shelter are especially valuable to their poorest human neighbors, many of whom depend on them as a source of protein. Roughly an eighth of the world’s population lives within 100 km of a reef. Corals also protect 150,000 km of shoreline in more than 100 countries and territories from the oceans buffeting (肆虐), as well as generating billions of dollars in tourism revenue.

Coral systems must adapt if they are to survive. They need protection from local sources of harm. Their eco-systems suffer from waste from farms, building sites and blast fishing. Governments need to impose tighter rules on these industrials, such as tougher local building codes, and to put more effort into enforcing rules against overfishing.

Setting up marine protected areas could also help reefs. Locals who fear for their livelihoods could be given work as rangers with the job of looking after the reserves. Visitors to marine parks can be required to pay a special tax, like what has been done in the Caribbean.

Many reefs that have been damaged could benefit from restoration. Coral’s biodiversity offers hope, because the same coral will grow differently under different conditions. Corals of the western Pacific, for example, can withstand higher temperatures than the same species in the eastern Pacific, which proves a way forward to encourage corals to grow in new spots.

5 . I shall never forget the day when the earthquake happened. It was about 5 in the afternoon and I was _________ along the road to my daughter’s school. Our plan was to go_________ together. I stopped at a_________ to get some fresh fruit. We liked to have some fruit to eat after our swim. I was driving along a high_________ on my way to the school. _________ my road was another road which was built like a_________. I was_________ so I put the bag of apples_________ me and started to eat one. Suddenly I saw the cars in front of me start to_________ from side to side. I slowed down. Then my car started to shake! I didn’t know what was happening. Perhaps something had__________ wrong with my car. I drove a little more slowly and then I__________ the car and at the same moment the road__________ onto the cars in front of me. I found myself in the__________. I couldn’t move. My legs and feet were hurt badly and I couldn’t move them. All around me was__________. But below me I could hear shouts and a lot of noises.

Then I realized what had happened. I had been__________ an earthquake. For about two hours nobody came. Luckily I could reach the bag of__________，so at least I had plenty to eat. Then I heard people__________ towards me. A team of people had come to__________ if anyone was under the__________ road. I called out, “I'm here！” I heard a shout. Soon a stranger climbed to my car. “How are you__________？” he asked. “Not too bad,” I said. They didn’t get me out until the next morning.

6 . Why do we like drinking water form plastic bottles? Some people think it is healthy and clean. Others drink bottled water because it’s easy — you can carry it around with you. In hot countries, like Greece, they often buy bottles of cold water in summer.

However, making lots of plastic is not a good idea for many reasons. First of all, we need a lot of oil for plastic products. We usually use oil as a source (资源) of energy. If we reduced the number of bottles we made, we wouldn’t need so much oil. Plastic bottles also pollute the environment. If we recycled all our plastic bottles, we wouldn’t need so much space for rubbish dumps. But in Greece, they don't recycle much of the plastic they use. In 2006, Greeks recycled only about 10% of plastic waste. The rest became rubbish on land and in rivers and seas.

So next time you want to throw away a plastic bottle in the litter bin, stop and think. If you recycled it, you would help the environment. But what can you do when there isn’t a recycling bin near you? Well, there are lots of useful ways that you can use your bottles again. For example, an empty bottle makes a great piggy bank for your pocket money, and if you cut a bottle in halves, you will have a plant pot. Go green! You can make a difference.