that some a couple of students
        
        
          haven't come to school
        
        
          today."
        
        
          "Yes, Saleem and Aisha
        
        
          are not here today."
        
        
          "Do you know why?"
        
        
          "They stayed home, Sir,"
        
        
          the class said. "They must be sick."
        
        
          "That means they must have played in the snow too long,"
        
        
          frowned the teacher.
        
        
          "We played in the snow too; will we get sick, teacher?" asked
        
        
          the class, alarmed.
        
        
          "If you aren't careful and stay out in the snow too long, you
        
        
          may do."
        
        
          "Why does snow make people sick? We love it when it snows.
        
        
          87