在一份有关膀胱癌与吸烟关系的前瞻性队列研究中，发现男性吸烟者膀胱癌发病率为48.0／

某金属元素R的碳酸盐化学式为R₂（CO₃）₃，则R元素的化合价为______，R元素的氢氧化物的化学式为______．

下列何项不是蒿芩清胆汤的药组

A.滑石，青黛 

B.陈皮，枳壳 

C.人参，茯苓 

D.黄芩，半夏 

E.甘草，竹茹 

《有序用电管理办法》是为落实科学发展观，加强电力需求侧管理，确保电网安全稳定运行，保障社会用电秩序，根据（）等法律法规制定。

A.《中华人民共和国电力法》

B.《中华人共和国合同法》

C.《电力供应与使用条例》

D.《电网调度管理条例》

Rapid application development (RAD) systems purport to lighten the developer’s (46) by making it easy to program an application with simple intuitive steps.

RAD tools (47) the developer everything needed to construct a fully functional application quickly and easily. They make short work of modifying the developed product to (48) changes after the program is finished. Applications developed with RAD tools are constructed as they are envisioned. As an application’s real usefulness (49) , the developer armed with RAD tools should be able to (50) on new features with little fuss.

（47）是（）

A.offer

B.order

C.refer

D.release

有整合营销传播先驱之称的舒尔茨曾经说过，在同质化的市场竞争中，唯有( )能够创造出差异化的品牌竞争优势。

A．质量
B．个性
C．定位
D．传播