如图所示的电路中，电源的电动势E和内电阻r恒定不变，电灯L恰能正常发光，如果变阻

自秦朝建立以来，君权与相权的矛盾、中央与地方的矛盾一直是古代政治体制演进过程中的重要问题，其实质是

A．权力分配和权力结构调整

B．不同集团和阶层的利益之争

C．强化职能和提高行政效率

D．稳定统治秩序巩固国家统一

一般容积大、水深深的湖泊、水库，水温常呈垂直分层型，上层温度较高，下层温度较低，中间的过渡带称为（）。

A.补偿层

B.中间层

C.温跃层

D.过渡层

Ink-jet printer belongs to nonimpact printers in which the characters are formed by projecting particles or droplets of ink on to paper. (71) printer is also a nonimpact printer in which the characters are produced by applying hot elements to heat-sensitive paper directly or by melting ink from a (72) on to plain paper. Electrostatic printer creates an electrostatic latent image, which is then made visible by a toner and transferred and fixed on paper. An electrostatic printer may be used in some instances as a (73) . Laser printer creates, by means of a laser beam directed on a (74) surface, a latent image which is then made visible by a toner and transferred and fixed on paper. Magnetographic printer creates, by means of magnetic heads operating on a metallic drum, a latent image which is then made visible by a toner and transferred and fixed on paper. Computer-output-microfilm (COM) printer produces on a photographic film a (75) of each page.

（71）处填（）。

A．Hot

B．Warm

C．Heat

D．Thermal

黄连姜汁炙用功偏

A．清上焦火
B．清相火，退虚热
C．清胃火止呕
D．泻肝胆实火
E．泻火凉血

（）模型是进行系统可靠性评估的基础。

A.系统停运

B.独立停运

C.元件停运

D.相关停运