It’s easy for people to  1  （catch）cold in winter or spring．But we can also do a lot   2  （stay）healthy．Here is some advice．

    Wash your hands often，and it will stop germs（细菌）  3  （pass）from one person to another．  4  （not use）your hands when coughing．Use a tissue（纸巾）、and then throw it away at once．Turn your head away from people near you when you   5  （cough）（咳嗽） ．Get some fresh air．Germs like staying in wet and warm room．So you’d better  6  （keep）your window open at night when you are sleeping，or you   7  （not have）enough fresh air．If flu（流感）is going around your house or school，you should  8  （try）to stay away from those who   9  （be） ill．Remember  10  （boil）your towel（毛巾）for about a minute to kill germs．

It's easy ________．

1. A.
   to stay health
2. B.
   stay health
3. C.
   stay healthy
4. D.
   to stay healthy