题干
We need to come up with a/an________and make a decision at once.
A：information
B：advice
C：idea
D：news
答案(点此获取答案解析）
C
We need to come up with a/an________and make a decision at once.
A：information
B：advice
C：idea
D：news
在其定义域内的一个子区间(k－1，k＋1)内不是单调函数，则实数k的取值范围是( )