单项选择题

Questions 18 to 20 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions.
Now listen to the passage.

What is the central idea in the passage you’ ve heard

A.Home training is more important than school training because a child spends so many hours with his parents.
B.Teachers can and should help parents to understand and further the objectives of the school.
C.Parents unwittingly have hindered and thwarted curricular objectives.
D.There are many ways in which the mathematics program can be implemented at home.