阅读下列短文，从每题所给的A、B、C和D项中，选出最佳选项。
Australia is
nearly as large as the United States, but most of it is too dry to live in.
Around the edge(边缘) of this huge dry part are large sheep and cattle farms. A
few of them are as large as the smallest states in America. Often the nearest
neighbors are many hundred miles away.
The two-way
radio is very important to people who live on these great Australian farms. It
works much like a telephone. A person can listen to someone else talk and give
an answer.
When these
radios first came into use, the Australian government set up a special(专门的，特别的) two-way radio
programme(节目). Then, people on the large farms could talk to a doctor
hundreds of miles away. They could tell the doctor about someone who was sick,
and the doctor could let them know how to care for the sick person.
Since the large
farms were so far from towns, the children could not to go to school. Radio
schools were set up for them in some places. At a certain time each day, the
boys and girls turn on their radios and listen to teachers in cities miles
away.
Families on the
large farms wanted to give news to their neighbors. “Round robin(知更鸟)” talks by radio
were started to keep families in touch with each other. They could talk about
who was getting married or who was sick or who was going away. The men could
talk about their sheep and cattle and how much money the markets would pay for
them. In many ways the radio became a newspaper for the farm people of
Australia.
