25. In the United States, sixteen, eighteen, and twenty-one are important ages in a person’s life.
(A) There are no special celebrations for these birthdays.
(B) Each of these is a time when a person can do new things to show that he or she is no longer
a child.
(C) In some countries, birthday celebrations continue throughout adulthood.
(D) People can do things to show that they have made the transition to adulthood.
¯