在分子筛运行到加热步骤时分子筛()输出一个信号启动再生气加热炉A、可编程控制器PLC

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问题:

在分子筛运行到加热步骤时分子筛()输出一个信号启动再生气加热炉

A、可编程控制器PLC

B、燃烧器控制箱

C、微机

D、燃烧器

考点:采油工考试海上采油工程仪表中级海上采油工程仪表中级题库
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烤瓷熔附金属冠修复时,上中切牙切端至少应预备出多少毫米

A.0.5
B.0.7
C.1.0
D.1.5
E.2.0

题型:单项选择题

电炉炼钢的短网导线即可用铜排,也可用铝排。

题型:单项选择题

Every day millions of letters go from one country to another. Letters mailed in Italy are received in Japan. Letters mailed in Canada are received in Africa. On the letters are many different kinds of stamps,bought in different countries.

The Universal Postal Union helps each letter get to the right place as quickly as possible. It sets up rules about the size and weight of letters,postcards,and small packages(包裹). It has rules that all countries must follow about international postal rates(费用).

One hundred years ago,international mail did not move so smoothly. One country did not always accept another country’s letters. Letters from some countries were too large to fit into the mailboxes of other countries. Letters travelled by many different routes(路线).Some were lost along the way.

Sometimes the person who sent the letter could pay only part of the postage. The person receiving the letter had to pay the rest.

The United States was the first to suggest that all countries work together to settle the questions of international mail. In 1974,men from twenty-four countries met in Switzerland to form the Universal Postal Union.Today,more than 120 nations belong to this union. From its office in Switzerland,the union helps the mail to move safely and quickly around the world.

小题1:From the story we can infer that ______.

A.mail is important to all countries

B.not enough letters are sent all over the world

C.all the letters must go to Switzerland first

D.all stamps look exactly the same小题2:The Universal Postal Union was formed ___________________ .

A.to help move mail quickly around the world

B.to give many men a chance to work

C.to help men meet in Switzerland

D.to look for the lost letters along the way小题3:The underlined word “postage” in this passage means __________ .

A.money paid when you buy a stamp

B.money spent on an envelope

C.the charge for carrying a letter by post

D.the pay a postman receives for his work小题4:This passage is mainly about ______________ .

A.different kinds of stamps in different countries

B.an organization that makes rules

C.international mail

D.the size and weight of letters

题型:单项选择题

增色效应的跳跃现象(jump o fhyperchromi clty)

题型:单项选择题

在同一长度的空气间隙和绝缘工具上进行电气试验,前者放电电压较后者()。

A.高一些

B.低一些

C.相同

D.不确定

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