It is a cold and dry winter morning. When you wake up, you feel that your throat hurts. You begin to sneeze and later you may cough. You must have a cold! Wait a moment. Could it just be a common cold or the flu (流感) that‘s been going around?
  A cold gives you a runny nose and cough. But it‘s usually easy to deal with. Some take medicine while others drink herbal tea or chicken soup. Usually you feel better after a week.
On the other hand, the flu can be much more dangerous. It usually gives you fever. Sometimes it can cause death. According to an American magazine, the worst flu in history killed about 50 million people from 1918 to 1919. And last year,over 34,000,000 people had flu in America and more than 20,000 of them died because of the flu.
  Don‘t worry. If you get a flu vaccine (疫苗), it can stop you from getting the virus (病毒). Flu vaccines work by giving the body a small amount of flu viruses. This causes your body to develop antibodies (抗体). So next time you get the flu, the antibodies should help you.
The flu virus changes every few years. Therefore, there are so many types of flu, such as H1N1 and H5N1. The antibodies for one type of flu can’t help us against all types of flu. That’s why we need to get the vaccine every year.
  However, good health habits may also help stop you developing a cold or flu. Washing your hands often helps stop you from getting viruses. It is also important to get regular exercise and eat healthy food. All these can help you strengthen your immune system (增强免疫系统).
(  )46. If you have a common cold, usually you’ll feel better after ________.
A. a week       B. two weeks       C. ten days        D. twenty days
(  )47. According to the passage, which is TRUE of the flu?
A. It first happened in 1919．    B. It usually doesn’t give you fever.
C. It is easy to deal with．      D. It can kill people sometimes.       
(  )48. If you get a flu vaccine, ________.
A. it can’t stop you from getting the flu virus  
B. it won’t cause your body to develop antibodies
C. your body will develop antibodies        
 D. your body will get a large amount of flu viruses
(  )49. We need to get a flu vaccine every year because ________.
A. we probably have a cold in winter   
B. the flu virus changes every few years
C. the flu is very dangerous       
D. you don’t need to take any medicine after that
(  )50. The following ways can help stop the flu EXCEPT ________.
A. staying indoors         B. getting regular exercise
C. eating healthy food     D. washing our hands often  

46-50 ADCBA