等体积的硫酸铝、硫酸锌、硫酸钠溶液分别与足量氯化钡溶液反应。若生成硫酸钡沉淀的质

题型:选择题

问题:

等体积的硫酸铝、硫酸锌、硫酸钠溶液分别与足量氯化钡溶液反应。若生成硫酸钡沉淀的质量比为1:2:3,则三种硫酸盐的物质的量浓度之比为(   )

A.1:2:3

B.1:6:9

C.1:3:3

D.1:3:6

考点:物质的量
题型:选择题

机械安全防护装置的一般要求中,紧急停止开关应区别其他开关,颜色为()。

A、红色

B、黄色

C、蓝色

D、绿色

题型:选择题

写出下列原子的相对原子质量H______O______C______S______

题型:选择题

Albert was an ordinary worker in an oil company in America. His workmates gave a nickname (绰号)“Four dollars a bucket of oil” below his name whenever and wherever he wrote down his name. As time went by, people forgot his real name. Later, when Rockefeller, the board chairman(董事长)of the oil company heard of it, he was very surprised, so he invited Albert to his office.

“Some people give you a nickname. Why aren’t you angry?” asked Rockefeller with some puzzlement in his eyes.

“Mr. Rockefeller, I like this nickname very much, because it is our company’s advertisement. When someone calls me ‘Four dollars a bucket’, I think it’s free advertisement for our company. It’s not necessary for me to get angry. Don’t you think so, Mr. Rockefeller?”

“What a wonderful man!” Rockfeller said excitedly when hearing Albert’s words. “Young man, work harder, you must be successful in the future! I believe in you!”

Five years later, Albert became the second board chairman after Rockefeller. Later Albert said in one of his reports, “I don’t think we should feel upset when we have no way to do the world—shaking things.” We should treat everything actively because maybe our future success will begin from a small thing!”

小题1:Albert was ___________in the oil company at the beginning.

A.a worker

B.an assistant

C.a manager

D.the second board chairman小题2:Albert wasn’t angry about his nickname because ____________.

A.he liked to have a nickname

B.it could make his workmates happy

C.he could become famous

D.it was a free advertisement for his company小题3:What is the main idea of this passage?

A.Rockefeller asked young people to work harder.

B.It’s very important to do small things well.

C.You can’t get angry when someone calls your nickname.

D.You should make more advertisements for your company.小题4:What did Rockefeller mean when he said “the world-shaking things”?

A.The big things

B.The interesting things

C.The small things

D.The frightening things小题5:What would be the best title for this passage?

A.I Believe in You

B.Albert and Rockefeller

C.Four Dollars a Bucket

D.The Second Board Chairman

题型:选择题

从天然药物中提取的有效物质,申请中药保护品种的保护期限和延长的保护期限分别为()

A.10年、10年

B.10年、20年

C.10年、14年

D.7年、7年

E.7年、10年

题型:选择题

产品质量主要有哪些特性?

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