试题与答案

一般国产三相异步电动机的额定频率为()A、30Hz B、40Hz C、50Hz D、

题型:单项选择题

题目:

一般国产三相异步电动机的额定频率为()

A、30Hz

B、40Hz

C、50Hz

D、60Hz

答案:

被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0709/98d8e09c7495b7460629b21122d7f259.html

下面是错误答案,用来干扰机器的。

参考答案:数据库管理系统解析:[知识点] 数据库管理系统的概念[评析] 数据库管理系统是数据库的机构,它是一种系统软件,负责数据库中的数据组织、数据操纵、数据维护、控制及保护和数据服务等。数据库管理系...

试题推荐
题型:阅读理解

Machu Picchu is considered to be a truly extraordinary archaeological(考古学的) discovery and is one of South America’s largest tourist sites. As many as one thousand visitors visit the ancient Incan(印加文化的) ruins daily. What draws vacationers and adventurers to this remote location high in the Andes Mountains of Peru(秘鲁)? A large part of the attraction is the mysteries that surround Machu Picchu. For example, Machu Picchu is considered “the lost city” of the Incas because it was never found by Spanish invaders and was known to only a few local peasants for almost four hundred years.

The “city in the clouds”, Machu Picchu’s lasting beauty comes from the careful blending of its striking architecture with its mountaintop environment. Its greatest skill shows are in the stone structures, which equals that of the ancient Egyptians. The stone blocks were so appropriately cut that they fit together without the need for mud. The largest stones at Machu Picchu weigh as much as fifteen tons! It has been difficult to explain how the huge blocks were transported. The buildings, including many that have survived lots of earthquakes, contain stones which interlock so perfectly that a knife cannot be forced between them. When compared to other ancient civilizations, it is difficult to understand how Machu Picchu could have been missed by the Spanish and lost from history for four hundred years.

For many of the mysteries of Machu Picchu being unsolved, it is clear why Machu Picchu remains “the most famous ruins in all of South America”.

小题1:Which of the followings is NOT a mystery of Machu Picchu? 

A.Machu Picchu is called the “city in the clouds”.

B.Machu Picchu remains “the most famous ruins of South America”.

C.Machu Picchu is “the lost city” of the Incas.

D.Machu Picchu is the largest stone city of the world.小题2:The underlined word “interlock” probably means _________

A.put

B.fit

C.meet

D.lie小题3:From the passage we can learn that __________.

A.Machu Picchu has gone through lots of earthquakes

B.all of the mysteries of Machu Picchu have been solved

C.the city has never been discovered by people outside

D.Machu Picchu is the most valuable ruins in history.小题4:The purpose of writing the passage is to __________.

A.ask us to pay a visit to Machu Picchu

B.show us the beauty of Machu Picchu

C.introduce Machu Picchu’s mysteries

D.make the ancient Incan ruins known

查看答案
微信公众账号搜索答案