决策支持系统能够支持( )。A．结构化与非结构化决策问题 B．结构化与半结构化决策

已知函数f（x）=-x²+2x．

（c）讨论f（x）在区间（-∞，c]上的单调性，并证明你的结论；

（2）当x∈[4，5]时，求f（x）的最大值和最小值．

___of the apple ___bad

A．Second-threes,goes

B．Two-threes,go

C．Two-third,goes

D．Two-thirds,goes

— Catherine, I've cleaned the room for you.

— Thank you. You _____ it. I could manage it myself. [ ]

A. needn't do

B. needn't have done

C. mustn't do

D. shouldn't have done

不适宜用吴茱萸汤治疗的病证是( )

A．脾胃阳虚，阴寒上乘，症见胸满而痛，甚至胸痛彻背者

B．肝寒上逆，症见头痛、干呕、吐涎沫者

C．肾阳不足，寒气内甚，症见吐利、手足逆冷者

D．肝寒犯胃，症见脘腹冷痛、呕吐酸水者

E．胃中虚冷，症见食谷欲呕者

厂焊钢轨的长度一般按（）加长来配轨。