Passage 1 　　Questions 21 to 25 are based on the following passage: 　　Is teaching important9. Well, of course it is.There was a time when the necessary knowledge could be taught to the young by family members. But as societies became more complex and division of labor more common, it was impossible for family members to teach the information and skills young people needed to become useful members of the society.As the need for specialists appeared, the job of teaching came into being in our county, and teaching as a job has been of increasing importance over the past hundred years. 　　Today, we have strict rules for teachers.We hope all children can attend schools.Many things tell us that teaching is indeed an "important" job.In recent years, there has been an increasing need for teachers to be " responsible ". This means that the public expects teachers to succeed in teaching important information to the young.Teachers’ salaries today, while not much, certainly are much higher than they were in past years. These increases have come about because people have realized that without enough salaries, people who have abilities will not beco~ne teachers.Today almost no one says that "anybody will do" for a teacher.The public expects "quality people" to teach the young, and progress is being made to give salaries that will make people who have abilities become teachers.

We know from the passage that (　　).

A．it is important to be successful in teaching the young
B．enough salaries are necessary in making quality people become teachers
C．greater progress has to be made in teaching
D．teaching is a product of the society’s division of labor