题干
—Are you free after school?
—Sorry: I’ve planned to treat a friend of mine to dinner for his help.
—Sorry: I’ve planned to treat a friend of mine to dinner for his help.
A：in term
B：in honor
C：in tur
D：in retur
答案(点此获取答案解析）
D
若对任意的
恒成立，则
的取值范围（ ）
