构成共同海损的条件有（）。A.必须是确实遭遇危难 B.必须是自然灾害造成的损失 C.

在如图所示的电路中，电源电压不变，闭合开关，电路正常工作。但过了一段时间，小灯泡发生断路，这时

A．电压表示数变大，电流表示数变小

B．电压表示数变大，电流表示数变大

C．电压表示数变小，电流表示数变大

D．电压表示数变小，电流表示数变小

Ⅰ型单组分聚氨酯防水涂料的断裂伸长率为（）。

A.≥300%

B.≥450%

C.≥550%

D.≥600%

Ravi, like many project (126) , had studied the waterfall model of software development as the primary software life-cycle (127) . He was all set to use it for an upcoming project, his first assignment. However, Ravi found that the waterfall model could not be used because the customer wanted the software delivered in stages, something that implied that the system had to be delivered and built in (128) and not as (129) .
The situation in many other projects is not very different. The real world rarely presents a problem in which a standard process, or the process used in a previous project, is the best choice. To be the most suitable, an existing process must be (130) to the new problem. A development process, even after tailoring, generally cannot handle change requests. To accommodate change requests without losing control of the project, you must supplement the development process with a requirement change management process.

A．parts

B．modules

C．software

D．a whole

关于艾滋病的抗病毒治疗，下列哪项是错误的（）

A．目前主张联合用药治疗

B．CD/T淋巴细胞大于0.5×10⁹/L者可以不治疗

C．当外周血HIV荷量为1000～10000拷贝/ml以上时应进行抗病毒治疗

D．有症状的患者应进行抗病毒治疗

E．无症状病人CD⁺₄T淋巴细胞低于0.5×10⁹/L应进行抗病毒治疗

燃气发生器是由（）组成的.

A.压气机，燃烧室和涡轮

B.气缸和活塞

C.静子和转子

D.螺旋桨和减速器