The influenza virus(流感病毒) or the flu is spread from person to person in the air when an infected
person coughs or sneezes.There are 3 types of the flu:
     -Type A viruses can infect people,birds,pigs,horses,seals,whales,and other animals,such as avian flu
or bird flu.
     -Type B viruses infect people and result in smaller outbreaks(爆发). People infected with type B
viruses are often hospitalized with higher death rates.
     -Type C viruses cause mild illness in humans without the onset of an epidemic (流行病).
Most people are familiar with the symptoms of the flu,but they can be mistaken for a severe cold.The flu
infection is far more serious and can cause severe health complications (并发症). There are many viral
infections that can cause flulike symptoms.It is better to visit your doctor so other possibilities can be
ruled out before your obtaining treatment.
     The flu virus attacks the body's cells and changes into different forms,which is why people who have
received the flu shot (流感疫苗接种) may still get ill with the flu.The influenza virus is transmitted_
through direct contact with infected persons such as by inhaling (吸入)droplets when they have coughed
or sneezed.It can also be spread by handling objects such as doorknobs and telephone receivers that an
infected person has been in contact with.
     If you have the flu,get plenty of bed rest and drink lots of fluids.Most people recover from the flu in
one to two weeks.Doctors often recommend flu vaccines( 疫苗) for highrisk groups such as young
children,the elderly,those with chronic(慢性的) diseases,weak immune systems,or professionals working with highrisk groups.

1. Which of the following is true about bird flu?
A. It is a disease which can spread among humans and animals.
B. Only animals and birds but not humans can be infected by this kind of virus.
C. This kind of disease can cause higher death rates among humans.
D. Bird flu won't cause the outbreak of an epidemic among humans.

2. When you cough or sneeze,a proper suggestion given by the writer is to ________.
A. take some medicine at once
B. see a doctor to make sure of the disease
C. drink more water
D. take more exercise and bed rest

3.  Why some people who have received flu vaccines are still down with the flu?
A. Because the flu is not easy to be treated.
B. Because the flu can spread from person to person.
C. Because people are easy to catch cold.
D. Because the flu virus may have different forms.

4. Once you are down with the flu,what should you do?
A. Take flu vaccines.
B. Improve immune systems.
C. Take enough bed rest.
D. Do more physical exercise.