下列函数中，既是奇函数，又在（0，+∞）上单调递减的函数是
[ ]
A.y=sinx
B.y=-|x|
C.y=-x3
D.y=x2+1
答案：C
It will ______ them 3 days to sort all the rubbish. [ ]
A. spend
B. cost
C. take
D. pay
脚手架的质量要求有哪些？
