中年阶段面临的问题是()。
_______themovieIwouldhavefinishedmypaperlastSunday.
设函数,其中n为正整数,则f'(0)=()
Theenginehasbrokenandtheboatis______onthewater.
Attendanceatfootballmatcheshave_____sincethecomingoftelevision.
设函数y=sinx^2+2x,求dy