下列所给出的函数中,是幂函数的是[ ]
A.y=-x3
B.y=x-3
C.y=2x3
D.y=x3-1
答案:B
Wherever one works, as a teacher, he or she should be erudite, patient and helpful.
A.strict
B.knowledgeable
C.considerate
D.serious
自来水的生产过程主要包括以下流程,其中发生化学变化的是