根据短文内容及所给首字母提示写出所缺单词， 并将完整单词填在下面对应题号后的横线上。
Air is very important to everything that lives. But the air we breathe is (1)g______ dirty. People all over
the world are looking for (2)w______ to make it clean again.
Have you (3)e______ watched the smoke from chimneys (烟囱) rising high in the air? Have you
(4)s______ the smoke from cars and trucks on roads or the smoke from planes? The smoke is not
(5)g______ to breathe. If we want to keep healthy and strong, we need to breathe (6)c______ air.
(7)W______ more and more factories everywhere and more and more cars, trucks and planes, it is
getting harder and harder to do with the air (8)p______.
Scientists have (9)a______ taken actions to stop or slow down some of the things that make the air dirty.
They will not stop working (10)u______ we have clean air again.
