题目内容
Sometimes vaccines（疫苗） do not provide lifetime immunity（免疫）. Some are only effective（有效）for a limited amount of time. In such cases， shots are necessary to maintain continuous vaccine protection. These shots are given at regular time. One vaccine， the flu （流感）vaccine， must be given every year. This is because there are many kinds of the flu.
A vaccine given in one year may provide protection against certain kinds of the flu virus， but when the next year’s flu season starts， vaccination against newer or different kinds may be required. Furthermore， flu vaccines do not provide protection for a lifetime. After as little as one year， protection may be far less than enough.
1.According to the passage， if you have a flu vaccine， you will be protected from flu _____________.
A.for a year B.for every year C.in the whole life D.for two years
2.The reason why one needs to have vaccine for flu every year is that____________.
A.flu cannot be cured B.flu can never die
C.flu would change every year D.flu never change
3.When the flu season starts， new_______ are needed.
A.patients B.viruses C.doctors D.vaccines
4.According to the passage， which of the following sentence is TRUE？
A.One must have flu vaccine. or he will die. B.Flu vaccines cannot protect a person for the whole life.
C.Vaccines never really protect people. D.Children should not be given vaccines.
5.What is the best title of the passage？
A.A Vaccine. Lifetime Immunity. B.Vaccine Can Protect You
C.How to Deal with Flu？ D.Vaccine Helps， but Not Lifetime Immunity
