______ , the red-feather currency fits the most satisfactory definition of the term "money".

单项选择题What is the writer's purpose in writing this passage（）

A．To explain how present-day reading habits developed.
B．To change people's attitudes to reading.
C．To show how reading methods have improved.
D．To encourage the growth of readin

单项选择题The development of silent reading during the nineteenth century indicated（）

A．a change in the status of literate people
B．a change in the nature of reading
C．an increase in the number of books
D．an increase in the average age of readers