— Alice, could you help me ________ the meat? I want to make some dumplings for dinner.
— OK. I'll do it right away.
A:put up
B:give up
C:use up
D:cut up
给出下列函数,(1)y=﹣8x;(2)y=-14;(3)y=8x2;(4)y=8x+1.其中,是一次函数的有____ 个.