—Would you mind picking up the last cigarette on the playground?
—_______. I'll do it right away.
A:Not at all
B:Of course
C:No way
D:Sounds good
①y随x的增大而减小;
②b>0;
③关于x的方程kx+b=0的解为x=2;
④不等式kx+b>0的解集是x>2.
其中说法正确的有____(把你认为说法正确的序号都填上).