阅读理解 Put 2 February in your diary! It is World Wetlands Day! It marks the date that the Convention(公约) on Wetlands was signed(签署)in1971.This special day was first celebrated in 1997 and it is celebrated every year. The celebration is a call for action. It is a way to show people how important and useful the wetlands are for people. On World Wetlands Day, people around the world takepart in many wetlands activities. People take trips to the local wetlands. There are talks about how important the wetlands are. People get together to clean up their local wetlands Children draw pictures to advertise the day. People also compete(比赛)in boat races. The World Wetlands Day is important! If there are no wetlands, there will be no water for anyone in the future. Wetlands help protect nature and resources(资源)like fresh water. Already,  more than 10000 million people in the world do not have fresh water. Many people do not know how important the wetlands are. They can understand why an elephant or a tiger is important because they are big, beautiful animals. It is much harder for them to understand how important the animals in the wetlands are. These small animals, such as frogs and snails, play a very important part in keeping the balance of nature. All plants and animals are part of the food chain(链).If the small wetlands animals die, some animals in the food chain will have nothing to eat. They will also die. People need the wetlands to keep the balance of nature in the world. If we do not protect nature today，it will be gone tomorrow. 46. What should you put in your diary? A. Some frogs. B. The date of World Wetlands Day. C. 1971 D. Any special day. 47. Where do people celebrate World Wetlands Day? A. All over the world.                        B. In ships C. At home.                                D. In their own way. 48. Which of the following sentences is NOT true? A. People celebrate World Wetlands Day by taking part in competitions. B. People celebrate World Wetlands Day by taking hips to local wetlands. C. People celebrate World Wetlands Day by listening to talks about the wetlands. D. People celebrate World Wetlands Day by talking about the weather. 49. Why are small animals important? A. They are part of the balance of nature and the food chain. B. They are beautiful. C. Bigger animals are eaten by them D. Without them, there may be no water. 50. Which of the following might be the best title of the article? A. Wetlands Are Important B. Small Animals Are Also Important C. World Wetlands Day D. Food Chain