villagers，more healthy，than，towns，air，fresh，all day in the fields，breathing fresh clean air，cities，full of smoke，dust，diseasePoeple in villages are healthier than people in towns That is because the air in villages is very fresh Farmers are working all day in the fields， breathing fresh clean air But there are too many factories in cities They produce more and more harmful gases At last， cities are full of smoke And there"s many dust in cities，too It may cause a disease So fresh air is very important to the people in cities We need fresh air So please don"t pollute the air!