- Our head teacher is responsible for his work. He spends most of his time with us.
- ________ He always communicates with our parents in his free time.
A:I hope so!
B:What?
C:That's for sure.
D:Why?
- Could you tell me _______?
- My cousin. He works as a policeman in the police station.
对于函数y=fx,如果存在区间m,n,同时满足下列条件:①fx在m,n内是单调的;②当定义域是m,n时,fx的值域也是m,n,则称m,n是该函数的“和谐区间”.若函数fx=a+1a-1xa>0存在“和谐区间”,则a的取值范围是( )
— Thank you.