同步电机定子旋转磁场具有的特点为( )。A．(A) 其磁极数和转_爱下问搜题

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问题单项选择题

同步电机定子旋转磁场具有的特点为( )。

A．(A) 其磁极数和转速与转子相同，但转向可不同

B．(B) 其磁极数和转向与转子相同，但转速可不同

C．(C) 其转速和转向与转子相同，但磁极对数不同

D．(D) 其转速和转向与转子相同，而且磁极对数也相同

答案

参考答案：D

阅读理解

The Longest Bicycle The longest true bicycle was 28.1 meters long and had two wheels. It was built by the students at the Delft University of Technology in the Netherlands. The bicycle was ridden more than 100 meters in Delft on December 11, 2002.	The Most Expensive Jeans A pair of Levis jeans which was over 115 years old then was sold by Randy Knight to a Japanese buyer over the Internet on June 15, 2005. The jeans cost the buyer $60,000.
The Heaviest Apple The heaviest apple weighed 1.849 kilos. It was grown by Chisato Iwasaki on his apple farm in Japan. Chisato picked the apple on October 24, 2005.	The Largest Mobile Phone The Iargest mobile phone was the Sony Ericsson W810i. It was 2.50×1.14×0.49m and was measured (量) at the MTN Scien Centre in Cape Town, South Africa, on September 20, 2007.

小题1:The longest bicycle ______.
A. was made in the USA.
B. couldn't be ridden
C. was about 100 meters long
D. had only two wheels
小题2:Which of the following is NOT true about the most expensive pair of jeans?

A．It was sold over the Internet.

B．It cost the buyer $60,000.

C．It was sold to an American buyer.

D．It is more than 100 years old now.

小题3:According to the passage, what happened on October 24, 2005?

A．The heaviest apple was grown.

B．The longest bicycle was built.

C．The largest mobile phone was made.

D．The heaviest apple was picked.

单项选择题 B型题

如果疑似鼠疫病人拒绝隔离治疗，医疗机构应报告的机构是（）

A.公安机关

B.卫生监督部门

C.卫生行政部门

D.疾病预防与控制机构

E.医疗机构