Our schools, according to the passage, ______.

单项选择题The main purpose of the passage is to ______.

单项选择题According to the passage, ______ has the greatest degree of control in an administered system.

单项选择题What is the main purpose of the passage

单项选择题According to the passage, a barter economy can lead to ______.

单项选择题In the second paragraph, the word real in real goods could best be replaced by ______.