题干
22.It is generally believed that teacher is ____it is a science.
A：an art much a
B：much an art a
C：as an art much a
D：as much an art a
答案(点此获取答案解析）
D
A：an art much a
B：much an art a
C：as an art much a
D：as much an art a
中自变量
的取值范围是（ ）
