机械技术档案能系统地反映机械物质形态运动的变化情况，是机械管理不可缺少的基础工作和科

妊娠合并心力衰竭

A．宫颈妊娠
B．子宫残角妊娠
C．腹腔妊娠
D．卵巢妊娠破裂
E．输卵管妊娠流产

6台拖拉机12小时耕地2160亩，平均每小时每台耕多少亩？（用两种方法计算）

患者，男，55岁，1周前右上腹绞痛，伴恶心、呕吐，体温37.4℃，予以抗炎治疗后缓解。3日来，出现巩膜黄染，纳差，收入院。查体：腹软，无压痛，Murphy征(-)，肝区轻叩痛。B超：胆囊9cm×5cm大小，其内多个点状回声，胆总管上段直径1.2cm，肝内胆管轻度扩张。

选择最佳手术方案应是

A．胆囊造瘘术

B．胆肠吻合术

C．胆囊切除，胆总管探查术

D．胆囊切除术

E．胰十二指肠切除术

Feasibility should be measured throughout the life cycle of system development. The scope and complexity of an apparently feasible project can change after the initial problems and opportunities are fully analyzed or after the system has been designed. Thus, a project that is feasible at one point may become infeasible later. The first feasibility analysis is conducted during the (1). The (2) represents a major feasibility analysis activity since it charts one of many possible implementations as the target for systems design. (3)  is a measure of how well the solution will work in the organization. It is also a measure of how people feel about the system. When it is determined in the later stages of the system life cycle, (4)  is often performed with a working prototype of the proposed system. This is a test of the system's user interfaces and is measured in how easy they are to learn and to use and how they support the desired productivity levels of the users. Economic feasibility has been defined as a cost-benefit analysis. The (5)  technique is a simple and popular method for determining if and when an investment will pay for itself.

空白（5）处应选择（）

A.payback analysis

B.return-on-investment analysis

C.present value

D.time value of money

货币的本质是（）

A.价值符号

B.流通手段

C.支付手段

D.固定充当一般等价物的商品