对人体安全的电压_______ ，当通过人体的电流接近30 mA时就会有生命危险

设备更新方案的选择，多为( )项目的选择。

A．寿命期相同的独立

B．寿命期相同的互斥

C．寿命期不同的互斥

D．寿命期不同的独立

配电设备结构应无变形，表面无损伤，指示仪表、按键和旋钮、机内部件无（）。

A.碰损

B.卡阻

C.脱落

D.损坏

李振声说：“几十年的经验使我深刻体会到，学点哲学的确可以使人做事情少犯错误，做研究少走弯路。”
下列观点与“国家最高科学技术奖”获得者李振声的上述感悟相一致的是( )。

A．哲学是各门具体科学的基础
B．哲学是人类对某一具体领域规律的概括
C．哲学是科学的世界观和方法论
D．哲学具有指导人们认识世界和改造世界的功能

DireCtor3D动画的制作过程是用提供的工具设置（）等效果，制作复杂的3D动画。

A.照相机

B.灯光

C.模型

D.阴影纹理

Under current federal law, employers are allowed to offer their employees free parking spaces as a tax-free benefit, but they can offer employees only up to $180 per year as a taxfree benefit for using mass transit. The government could significantly increase mass transit ridership by raising the limit of this benefit to meet commuters’ transportation costs. The proposal above to increase mass transit ridership assumes that

A．current mass transit systems are subject to unexpected route closings and delays.

B．using mass transit creates less air pollution per person than using a private automobile.

C．the parking spaces offered by employers as tax-free benefits can be worth as much as $2,500 per year.

D．many employees are deterred by financial considerations from using mass transit to commute to their places of employment.

E．(E) because of traffic congestion on major commuter routes, it is often faster to travel to one’s place of employment by means of mass transit than by private automobile.