Many of the Earth’s plants and animals have already died out, and a hundred species become     1     (endanger) every day. If nothing is done, we may find ourselves alone on Earth.

The population of wildlife species has dropped     2     (main) due to the loss of habitats. The forests that wild animals live in are being destroyed by people. As       3     result, their living area has become smaller and smaller,     4     leads to the shortage of food. Besides, many animals are dying out because of all kinds of pollution     5    (cause) by humans in the process of the     6    (develop) of society. At the same time, man is killing off animals just for     7    (get) their fur, teeth and meat.

I suggest that measures should be taken     8    (protect) wildlife. The government should keep people     9    destroying forests and shut down the factories that pollute rivers and air. I think more wildlife     10    (reserve) should also be built. In this way, we can save more wildlife species and make the world a better place.

Polar bears live in a special environment that is too cold for most animals. For much of the year, they live and hunt on the     1     (freeze) Arctic sea ice. Nature has prepared them for the cold conditions but nothing has prepared them for the danger     2     threatens (威胁) their only home.

The polar bears’ world is melting. Polar bears     3     (suffer) in a warmer world are in danger. Studies show that the polar ice     4     (decrease) by 9.8% every 10 years since 1979. At present, about 20,000 to 25,000 polar bears live in the Arctic. Polar bears depend on the sea ice for their     5     (survive). “The sea ice is more than just the platform that the bears walk     6    ,” says Andrew Derocher, who studies North American polar bear populations. “Without     7    , they can’t exist.”

Some melting and refreezing of the sea ice is     8     (nature). But in a warmer world, these cycles speed up, and bears have less time to hunt.     9     (normal), they have three months in the spring when they gain more weight and the extra fat is used later, when the bears are not actively hunting.     10     it is important to protect the environment and keep the ecological balance.

The Yangtze River is the third longest river in the world. However, rapid development and     1     (increase) population have meant that the amount of water     2     (take) from the river     3    (be) rising, and the waste being put back into the river has been increasing.

    4     (luck), the health of the Yangtze River has raised concern     5     in China and abroad. Many people have recognized the importance of protecting it and many environmental     6    (organize) and projects have been set up. The Green River organization, for example, educates people on the importance of protecting this great river. Besides, two special government projects are on    7     way. One is the water and soil preservation project,     8    resulted in farmers     9    (replace) their crops with trees or grass. The other includes nature reserves for white-flag dolphins.

Because of this, the environmental situation of the Yangtze River is improving, but we still have a long way to go     10    (solve) all the problems.