The population of the Earth is growing faster. It is important that we look after the Earth. We need it! The Earth gives us a lot of things. We also give the Earth a lot, but some of the things are not good.

   In nature, when something dies, other animals and plants get food from it. Every animal or plant gives food for other animals or plants. However, animals can't get food from many of the things that we "give" the Earth. Animals and plants can't eat metal, plastic and glass. These things will stay in the ground for many, many years.

   Some rubbish is very dangerous for plants and animals. In some places, many animals live together. One animal makes food for many more animals. If we put rubbish and chemicals in the water, the plankton(浮游生物) can die. If there isn't any plankton, many animals have nothing to eat.
   So what can we do? Don't leave any rubbish in the countryside! Don't make so much rubbish!

阅读理解

     Most of you know this mathematical game, of course. You and your friend draw crosses and circles on a sheet of paper. You do it one after another. The first pupil who gets three marks in a row wins. But do you know that you can play this game another way and it will become more interesting? You must try to make your friend win. If you get your three marks in a row, you don't win — you lose!

     It is more difficult to play this game the other way. The second pupil can always win (if he plays the right way), but he may not win if the first pupil begins with his mark in the center. Then if the first pupil always takes a place on the other side of his friend's mark, nobody will win.
     If your friend does not know the secret which we have explained, you must play each time so as to leave him the greatest number of ways to win. You may try a few games and you will see how interesting it is to play the game this way.

    Cruises are becoming more and more popular, with around 20 million passengers per year now enjoying holidays on board luxury ( 奢侈的 ) ships. More people see a cruise as the perfect way to sit back and do nothing, and enjoy time off work. But what is the effect on the environment of this trend?

    Although it usually takes less energy for a vehicle to move through water than over land, cruise ships are often massive, with the biggest ones carrying up to 6,000 passengers. Moving such large vehicles requires huge engines which bum as much as 300,000 litres of fuel a day. One scientist has calculated that cruise ships create as much pollution as 5 million cars going over the same distance. Because they are out at sea, they also burn dirtier fuel that isn't allowed on land. Unfortunately, no government has control over the amount of air pollution out at sea. Cruises also produce huge amounts of rubbish, and cruise ships aren't usually good at recycling. Waste water from showers and toilets is usually poured directly into the sea - as much per day as from a small town. Waste food from restaurants isn't put into the sea, but still causes problems when brought back to the land.

    Cruise ships also cause difficulties in the cities where they stop. Popular destinations can get five or six ships per day, with thousands of tourists at a time. Good for restaurants? No. Restaurant owners complain that the visitors look around for a few hours and then return to their ship to eat. What's more, the crowds can put off other tourists, who complain that the streets are too busy.

    Some towns have banned (禁止) cruise ships or put a limit on the number that can stop at the same time. People who care about the environment worry that as the cruise industry continues to grow, so will the issues for our planet.

Until the beginning of July, there has been no rain in northern Italy for over 100 days. Add to that the high temperatures, and the locals get very dry conditions. This is the most serious dry spell（干旱期）for that area in the past 70 years. Because of this situation, the country's longest river, the Po, is drying up!

This is bad news for several different reasons. The fresh water of the Po provides drinking water for northern Italy. Besides, farmers in this area need the water of the Po to keep their crops growing. What's more, the flowing river water is used to create about half of the hydroelectric power（水力发电）for Italy. Its drying up means that more natural gas（天然气） will be used, which is bad for the environment.

There have been some interesting discoveries from this lack of rain, however. Between Florence and Milan, a long ship sunk （沉没）in 1943 appeared because of the low water levels of the river. Now many tourists and locals come to see this ship. A German tank has also appeared out of water near Mantua. At other places along the river, people can even walk on the sandy river bed. Although this may be interesting, people in Italy and around the world are hoping for the return of rain to refill the Po!