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请指出所示实验操作中的错误，并改正：

(1)错误：___________________________________________________________________

改正：___________________________________________________________________ 

(2) 错误：_______________________________________________________________

改正：___________________________________________________________________  

(3) 错误：________________________________________________________________

改正：___________________________________________________________________ 

答案

(1)错误：

①手持试管加热②试管垂直放置③试管中液体超过试管容积的④用酒精灯内焰加热

改正：①用试管夹夹持试管②试管与桌面成45 °角③将试管中液体倒出部分，使其不超过试管容积④用酒精灯外焰加热

(2)错误：①瓶塞没有倒放在桌面上②试管垂直放置③试管口没挨试剂瓶口（远离试管口）

改正：①瓶塞倒放在桌面上②试管略倾斜③试管口紧挨试剂瓶口

(3)错误：试管口向上倾斜

改正：试管口略向下倾斜

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选词填空。
first,    we,    million,    good,    expensive,    work ,
surprise,    stop,    develop,    university
      We are all busy talking about and using the Internet, but how many of   1   know the history of the Internet?
      Many people are   2   when they find that the Internet was set up in the 1960s. At that time, computers were
large and expensive. Computers network didn't work   3  . If one computer broke down, then the whole network
  4  . So a new network system had to be set up. This was why computer network system would keep on   5   
all the time.
      At   6   the Internet was not only used by the government, but in the early 1970s,   7  , hospitals and banks
were allowed to use it, too. However, computers were still very   8   and the Internet was difficult to use. By the
start of the 1990s, computers became cheaper and easier to use. Scientists has also   9   software (微软) that
made "surfing" the Internet more convenient. The Internet has now become one of the most important parts of
people's life. 
      Today it is easy to get on-line (上网) and it is said that   10   of people use the Internet every day. Sending
e-mail (电子邮件) is more and more popular among students.
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小肝癌是指内径（）的癌肿，其回声强度多为（）。
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