粮食产量增产11%，记作+11%，则减产6%应记作______．
∵增产11%，记作+11%，
∴减产6%应记作-6%．
故答案为：-6%．
设函数f（x）=xsinx的导函数为f′（x），则f′（x）等于（ ）
A．xsinx+xcosx
B．xcosx-xsinx
C．sinx-xcosx
D．sinx+xcosx
Never ________ forget the days when ________ together with you. [ ]
A. shall I; did I live
B. shall I; I lived
C. I shall; I lived
D. I shall; did I live
