电动机的制动有哪四种？

主动脉瓣关闭不全（）

A．心尖部可触及舒张期震颤

B．心尖搏动减弱或消失

C．心尖搏动向左下移位呈抬举性

D．胸骨右缘第2肋间收缩期震颤

E．胸骨左缘第2肋间收缩期震颤

药品批发企业（）

A．是指药品监督管理部门对药品研制、生产、经营、使用单位实施相应质量；管理规范进行检查、评价并决定是否发给相应认证证书的过程 

B．是指药品批发和药品零售 

C．是指将购进的药品直接销售给消费者的药品经营企业 

D．是指将购进的药品销售给药品生产企业、药品经营企业、医疗机构的药品经营企业 

E．是指经药品监督管理部门核准经营药品的品种类别

下列肿瘤细胞中明显异型、核大而不规则，且核分裂活跃的是（）

A.卵黄囊瘤

B.胚胎性癌

C.Leydig细胞瘤

D.精原细胞瘤

E.颗粒细胞瘤

The Rational Unified Process (RUP) is a software engineering process, which captures many of best practices in modern software development. The notions of (21) and scenarios have been proven to be an excellent way to capture function requirements. RUP can be described in two dimensions - time and content. In the time dimension, the software lifecycle is broken into cycles. Each cycle is divided into four consecutive (22) which is concluded with a well-defined (23) and can be further broken down into (24) - a complete development loop resulting in a release of an executable product, a subset of the final product under development, which grows incrementally to become the final system. The content structure refers to the disciplines, which group (25) logically by nature.

21（）

A.artifacts

B.use-cases

C.actors

D.workers

下列物质在分子筛上的吸附从强到弱正确的排列顺序为（）。

A、H₂、N₂、CO、CO₂、CH₄、H₂O

B、H₂、N₂、H₂O、CO₂、CH₄、CO

C、H₂、H₂O、CO、CO₂、CH₄、N₂

D、H₂O、CO₂、CH₄、CO、N₂、H₂