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 小题1: dirty. People all over the world are looking for w 小题2: to make it clean again.
Have you ever watched the smoke from chimneys(烟囱) r 小题3: high in the air? Have you s 小题4:___ the smoke from cars and trucks on roads or the smoke from planes? The smoke is h 小题5: to everyone, especially old people and children. If we want to keep well and strong, we need to breathe f 小题6: air.
With more and m 小题7: factories everywhere and more and more cars, trucks and planes, it is getting harder and harder to do with the air p 小题8: .
Scientists have a小题9: found ways to stop or slow down some of the things that make the air dirty. They will not stop working u 小题10: we have clean air again.
