A:besides ,has been felt
B:by, feels
C:near, is felt
D:beside has felt
细菌属于原核生物,与真核生物最主要的区别是____.
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( )