There’s nothing gradual about the flu: it hits you like a hammer. One minute you’re feeling fine, and the next you can be shivering, burning up, and then shivering again. In minutes, your legs become weak and your body aches in places that have never hurt before. Influenzacan break out so suddenly that people can sometimes say, “It hit me at exactly 9 last night.” But whether the flu strikes at night or on the bus to school, there’s just one thing a victim wants to do: lie down in bed. A healthy person can fight off the flu in three to five days, though a cough and tired feeling can last two more weeks. But often an attack of the flu is followed by another illness. Doctors recommend that old people, or people of nay age with heart or lung problems, get a flu vaccine every year. Because flu viruses change all the time, a new vaccine must be prepared each year to protect against future attacks.

　　The flu is such an infections illness that it can hit you any time and anywhere. One minute you can be feeling fine, and the next you can be shivering, burning up, and then shivering again. Soon your legs become weak and your body begins to ache. Once the flu hits you, you just want to lie down in bed. Usually, it lasts three to five days, buy is often followed by another illness. If you’re old or have heart or lung problems, you’d better get a flu vaccine every year so as to protect against it.