化学电池在通讯、交通及日常生活中有着广泛的应用．目前常用的镍（Ni）镉（Cd）

电池，其电池的总反应为：Cd+2NiO（OH）+2X⇌2Ni（OH）₂+Cd（OH）₂以下说法正确的是（　　）

①充电时化学能转变为电能②放电时化学能转变为电能

③充电过程为物理变化④放电过程为化学变化⑤X物质的化学式为H₂O．

A．②④⑤

B．①③⑤

C．②③⑤

D．①③④

Wes Smith, CFA, refers many of his clients to Bill Towers, CPA, for accounting services. In return, Towers performs routine services for Smith, such as his tax returns, for no charge. Towers has just become a member of CFA Institute. With this development, Towers must:()

A. reveal to the prospects referred by Smith that he performs services for Smith, along with the estimated value of those services.

B. only reveal to the prospects referred by Smith that he performs services for Smith.

C. reveal nothing about his relationship with Smith since they are now both members of CFA Institute.