Farming in Europe is big business. About     21     of the country’s land is used for agriculture, producing much of the food the European countries need. Most farms are very big and use large     22     of chemicals to help crops grow. People want more farms to become organic. They believe that smaller farms, using     23     growing methods, will lead to better and safer foods. They also think organic farming will be safer for the environment.

To grow and protect crops, farmers often use fertilizers(化学)and pesticides(农药). Fertilizers help make the soil more productive. Pesticides kill insects and     24     diseases that might destroy crops. Most of the fertilizers and pesticides used in modern farming     25     chemicals.

Some people believe the use of these chemicals on crops is bad for the environment and for people’s health.

Organic farmers avoid using products     26     chemicals. They have to find other ways to keep the oil productive and to keep pests away from their crops. Organic farmers do not use drugs to make animals grow larger or faster. They also do not grow crops that have been developed by science.

For more than 30 years, scientists have been arguing about how rainforests like the Amazon might have reacted to the cold dry climates of the ice age, but until now, no one has reached a satisfying answer.

Rainforests like the Amazon are important for mopping up CO₂ from the atmosphere and helping to slow global warming. Nowadays, the trees in the Amazon take in around 500 million tons of CO₂ each year; equal to the total amount of CO₂ giving off in the U. K. each year. But how will the Amazon react to future climate change? If it gets drier, will it still survive and continue to draw down CO₂? Scientists hope that they will be able to learn in advance how the rainforest will manage in the future by understanding how rainforests reacted to climate change in the past.

On the one hand, getting into the Amazon rainforest and collecting information are very difficult. On the other hand, to study past climate, scientists need to look at fossilized pollen (花粉) kept in lake mud. Going back to the last ice age means drilling deep down into lake sediments (沉淀物), which requires specialized equipment and heavy machinery. There are very few roads and paths, or places to land helicopters and planes. Rivers tend to be the easiest way to enter the forest, but this still leaves vast areas between the rives completely unsampled. So far, only a handful of cores have been drilled that go back to the last ice age and none of them provide enough information to prove how the Amazon rainforest reacts to climate change.

The Earth has warmed by about l℃ over the past 100 years. Scientists say that this is because some human activities have d    50     nature. Global warming may bring changes in rainfall and a rise in sea levels. It may put human beings in serious danger. But is there anything that can be done?

Buying green

When you’re in the supermarket with your parents shopping for an oven or a washing machine, keep your eyes o    51    . There are labels (标签) that tell which machine save e    52    . They may be a little more expensive but they use less power.

Make yourself an expert

Learning about the environment is very important. There are many good books that will help you. To get started, ask a teacher for some s    53    . You can also surf the Internet to find websites with information about the environment and climate change.

Open the window

A large part of the carbon dioxide (二氧化碳) comes from our homes. But there are easy ways of cutting the a    54     down. Open a window rather than turning on the air conditioner. If you have to use it, put the temperature setting (装置) 2 degrees h    55     in summer and 2 degrees lower in winter. Use the dishwasher only when it’s full.

Save paper

When it’s time for your family to pay telephone or credit cards (信用卡) bills, help your parents to do it online. By not using paper, you are saving trees. It also helps cut the amount of fuel (燃料) used by the trucks and planes that transport paper bills. Be c    56     with the personal information and report problems at once. What’s more, paying online is handy and quick.