The carriers’ participation in the system is determined by ().
A. the US federal government
B. mobile phone users
C. the carriers themselves
D. the law of the United States
Florence Nightingale In 1837, to the age of seventeen, Florence Nightingale decided to become a nurse, (51) horrified her dear mother. In (52) days, nurses were little more than doormen, and hospitals were places of dirtiness and (53) . Nightingale pressed on and in 1853 she became president (54) a small London hospital. She went on to the Crimea when war (55) there between Britain and Russia. She (56) the first of what we now know (57) war hospitals: sanitary. safe, and stocked with supplies. Her tireless ministrations (照料) to the (58) soldiers made her famous all (59) the world. Following the War, Nightingale (60) fame and continued to train nurse, ever battling (61) what she herself declared "a commonly received idea...that it requires nothing (62) a disappointment in love, or incapacity in other things, to turn a woman (63) a good nurse." Since 1921, her birthday (64) the centerpiece of National Hospital Week, (65) in British and American hospitals with special exhibitions, workshops, and publicity drives.
A. is
B. was
C. has been
D. had been