先通读下面的短文，然后根据短文内容，在文章后表格的空格内填入一个最恰当的单词。每个空格只能填一个单词。
Every time we turn on the TV or take a ride in a car, we could be adding to a problem called acid rain(酸雨). In this article, we’ll learn something important about acid rain.
The formation of acid rain
When people use fuels (燃料), such as coal and gasoline(汽油), poisonous（有毒的） gases are given off. When these gases come together with rain, acid rain forms. Many power stations burn fuels in order to create the electricity(电) that we use in our homes and offices every day. Cars and trucks also send these gases into the air when they burn gasoline. When rain meets these gases, harmful things called acids form. This is acid rain.
The harm of acid rain
Acid rain destroys（破坏） everything. It poisons our rivers, ponds and lakes and oceans along with the life in them. It pollutes our soils and crops, harm trees, and can cause the death of fish and plants. Acid rain also eats away at our buildings.
The prevention of acid rain
We need to reduce and even stop the pollution that gets into our air. Turn off lights, televisions and other electrical appliances(电器) if we are not using them. Walk and take a bike whenever possible. If we are travelling a long distance, take a bus or train to save fuel.
As research shows, acid rain harms our environment. But people everywhere can take small steps now to help protect our environment and make our children change.

Whenever we use electricity or drive our cars we may add something bad to the air around us. And even worse, we may cause a terrible problem—acid rain.
The formation of acid rain	When fuels, such as coal and gasoline are burnt, harmful gases are sent into the air. When these gases        with rain, acid rain forms.
The harm of acid rain	Acid rain is greatly       to the environment. It makes our rivers, ponds and lakes and oceans dirty and       fish and plants. And it can corrode (腐蚀) the buildings we live in.
The prevention of acid rain	Trying to prevent the pollution that gets into the air is        . Keep the electrical appliances off while they are not in use. We can also use different ways of traffic to make less use of fuels.
Research tells us that acid rain harms our environment. So people around the world can take small steps now to    our kids.