A．were immunologically defenseless against measles
B．could scarcely ward off the fatal attack by the 1952 epidemic
C．were the last native people to be struck by a virgin-soil epidemic
D．didn't come into frequent contact with White Americans until the 20th century

A．eleven years old
B．sixteen years old
C．twenty-one years old
D．between twelve and twenty-one years old

A．in the late 19th century in the United States the dividing line between adolescence and adulthood no longer existed
B．no one can marry without the permission of his parents until the age of twenty-one
C．one is not free from the restrictions of child labor laws until he can join the army
D．one is considered to have reached adulthood when he has a driver's license

A．the older one becomes, the more basic rights he will have
B．one won't get more basic rights than when he was 21
C．one will enjoy more rights granted by society
D．one will obtain more basic rights

A．graduations from schools and colleges
B．social recognition
C．socio-economic status
D．certain behavioral changes

A．the definition of maturity has changed
B．the industrialized society is more developed
C．more education is provided and laws against child labor are made
D．ceremonies for adolescence have lost their formal recognition and symbolic significance

A．one objective will confuse the selected audience
B．a set of objectives will help to attract new employees
C．one objective will make the selected audience know what to do
D．a set of objectives will help the selected audience know more about the campaign

A．find a suitable creative approach
B．develop an effective campaign
C．create a progressive image
D．establish the objectives

A．Radio and television
B．Newspaper and radio
C．Magazine and television
D．Newspaper and magazine

A．it minimizes quarrels
B．it cuts down the number of drivers
C．most drivers will hit you if offended
D．most drivers never make acknowledgements