先阅读短文，掌握其大意。然后从方框中所给的词中选出恰当的10个，并用其适当形式填空，每个词限用一次。(每小题1分) stop, though, sleep, their, bad, city, ill, we, start, fresh, please, breath Villagers are healthier than people who live in towns. One reason for this is that country air is 小题1: than the air in smoky 小题2: . The villager is 小题3: fresh clean air all day in the fields, but the air the townsman breath is always full of smoke and dust. We cannot live without air. If we are 小题4: from breathing even for five minutes, we will die. Bad air means bad health and certain kinds of 小题5: , which may kill us, 小题6: they may not kill us at once. We all know 小题7: feelings we will get if we stay a long time in a shut, crowded room. After a time, we begin to feel very 小题8: , and can hardly keep our eyes open. Then our heads begin to ache, and the longer we stay the 小题9: we feel. How nice it is when we get outside into the fresh air! We must, therefore, keep 小题10: windows open, so that air in our rooms is always fresh.