后发性白内障是指（）。

A.外伤引起晶状体混浊

B.由眼底退行性病变引起晶状体混浊

C.由药物引起的晶状体混浊

D.由代谢障碍引起晶状体混浊

E.白内障囊外摘除术后残留的皮质及囊膜混浊

Your plan is far from satisfaction , so you must _____ more time and energy to it.[ ]

A. earn          

B. spend        

C. devote        

D. waste