问题 填空题 案例分析题

萘乙酸(NAA)是科学家通过化学的方法合成和筛选的在结构和生理作用方面与生长素相似的物质,其生理作用也与浓度密切相关,探究萘乙酸(NAA)对扦插枝条生根作用的最佳浓度范围,在农业生产的应用上具有非常重要的意义。

实验的自变量是(),实验过程中,温度、处理时间等要一致,其原因是()。

答案

参考答案:萘乙酸的浓度;对照实验要遵循单一变量的原则(控制无关变量)

选择题
阅读理解

阅读理解。

     The most frightening words in the English language are, "Our computer is down." You hear it more

and more when you are on business. The other day I was at the airport waiting for a ticket to

Washington and the girl in the ticket office said, "I'm sorry, I can't sell you a ticket. Our computer is

down."

     "If your computer is down, just write me out a ticket."

     "I can't write you out a ticket. The computer is the only one allowed to do so."

     I  looked down on the computer and every passenger was just standing there drinking coffee and

staring at the black screen. Then I asked her, "What do all you people do?"

     "We give the computer the information about your trip, and then it tells us whether you can fly with

us or not."

     So when it goes down, you go down with it."

     "That's good, sir."

     "How long will the computer be down?" I wanted to know.

     "I have no idea. Sometimes it's down for 10 minutes, sometimes for two hours. There's no way we

can find out without asking the computer, and since it's down it won't answer us."

      After the girl told me they had no backup (备用) computer, I said. "Let's forget the computer. What

about your planes? They're still flying, aren't they?"

     "I couldn't tell without asking the computer."

     "Maybe I could just go to the gate and ask the pilot if he's flying to Washington, " I suggested.

     " I wouldn't know what gate to send you to. Even if the pilot was going to Washington, he couldn't

take you if you didn't have a ticket."

     "Is there any other airline flying to Washington within the next few hours?"

     "I wouldn't know, " she said, pointing at the dark screen. "Only 'IT' knows. 'It' can't tell me."

     By this time there were quite a few people standing in lines. The word soon spread to other travelers

that the computer was down. Some people went white, some people started to cry and still others kicked

their luggage.

1.  The best title for the article is _______.

A. When the Computer Is Down            

B. The Most Frightening Words

C. The Computer of the Airport          

D. Asking the Computer

2.  What could the girl in the ticket office do for the passengers without asking the computer?

A. She could sell a ticket.    

B. She could write out a ticket.

C. She could answer the passengers' questions.

D. She could do nothing.

3.  Why do you think they had not a backup computer?

A. Because it was easy down              

B. Because it was very expensive.

C. Because it was not advanced enough.

D. Because it was not as big as the main computer.

4. The last paragraph suggests that _______.

A. a modern computer won't be down.

B. computers can take the place of humans

C. sometimes a computer may bring suffering to people

D. there will be great changes in computers