【正确答案】 C

【答案解析】[解析] weaken意为“使……虚弱，削弱”，符合本题题意，如：The illness weakened her heart．疾病使她的心脏衰竭。A．appreciate则作“欣赏，感谢”讲，如：I'd appreciate it if you would turn out the lights．劳驾你把灯关上。B．confirm意为“加强，使……更坚定，证实”，如：I am confirmed in my belief．我的信仰更加坚定了。D．cherish作“爱护，抱有，怀有”讲，如：He chef shed the memory of his dead wife．他念念不忘亡妻。