根据短文内容及首字母提示,填写所缺单词,使短文意思完整。每空限一词。
Air is very important to everything that lives. But the air we breathe is g dirty. People all over the world are looking for w to make it clean again.
Have you ever watched the smoke from chimneys(烟囱) r high in the air? Have you s ___ the smoke from cars and trucks on roads or the smoke from planes? The smoke is h to everyone, especially old people and children. If we want to keep well and strong, we need to breathe f air.
With more and m factories everywhere and more and more cars, trucks and planes, it is getting harder and harder to do with the air p .
Scientists have a found ways to stop or slow down some of the things that make the air dirty. They will not stop working u we have clean air again.