问题 探究题

如图所示,甲、乙两个电路都可测量Rx的电阻,由于电流表和电压表都有内阻,所以甲图测量的电阻Rx________,乙图测量的电阻Rx________(填“偏大”或“偏小”).甲图出现这种情况的原因是________________________.

答案

偏大;偏小;

电流表有内阻,电压表测量的是Rx和电流表的总电压或电压表测量的电压比Rx两端电压大,所以测量的电阻偏大.

单项选择题 A3/A4型题
阅读理解

阅读理解。

     The Forbidden City (Imperial Palace) in the heart of Beijing is the largest and most complete imperial

palace and ancient building complex in China, and the world at large. Its construction began in 1406 and

was completed 14 years later, having a history so far of more than 580 years. Twenty-four emperors from the Ming and Qing dynasties lived and ruled China from there. Most of the buildings in the Forbidden City were rebuilt many times, although they maintained the original architectural style.

     The Forbidden City, extending 753meters from east to west, and 961 meters from north to south

makes a rectangular shape and covers a total area of 720,000 square meters. It consists of several dozen

compounds of varying sizes and some 9,900 bays of rooms, with a total floor area of 150,000 square

meters. Most of the buildings were built with wood, roofed with yellow glazed tiles(琉璃瓦)and built on

blue-and-white stone foundations, looking solemn and brilliant. City walls are 10 meters high, and a

52-meter-wide moat(护城河) surrounds the Forbidden City. Three- storied towers are placed at each

corner of the wall.

     The buildings of the Forbidden City fully embody the artistic features and style of ancient Chinese

palace architecture, and can be called a masterpiece in Chinese, even the world, architectural history.

Today, as the largest museum of cultural relics in China, the Forbidden City, also called the Palace

Museum, collected and displayed about one million precious historical relics from the Shang dynasty (16th century B.C. - 11th century B. C. ) to the Qing dynasty. It was made part of the world cultural heritage

list in 1987.

1. From the text we know that the shape of the Forbidden City is _____.

A.  

B.   

C. 

D. 

2. The underlined word "maintained" in the first paragraph means _____.

A. continued

B. kept

C. supported

D. contained

3. The reason why the buildings of the Forbidden City can be called a masterpiece in Chinese architectural history is that _____.

A. twenty-four emperors lived and ruled China there

B. it has a history of more than 580 years

C. it makes a rectangular shape and covers a total area of 720,000 square meters

D. the buildings there fully embody the artistic features and style of ancient Chinese palace architecture

4. The earliest historical relics collected and displayed in the Palace Museum may have a history of _____. A. about 600 years

B. over 580 years    

C. over 3,000 years

D. nearly 100 years