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问题 单项选择题

细胞学说最初是由哪位（些）学者提出的（）

A.S.Cohen

B.M.J.Schleiden

C.T.Schwann

D.J.D.Robertson

E.M.J.Schleiden和T.Schwann

答案

参考答案：E

改错题
短文改错：对标题号的每一行作出判断：如无错误，在该行右边横线上划一个勾（√）；如有错误
（每行只有一个错误），则按下列情况改正：
1. 该行多一个词：把多余的词用斜线（\）划掉，在该行右边横线上写出该词，并也用斜线划掉。
2. 该行缺一个词：在缺词处加一个漏字符号（∧），在该行右边横线上写出该加的词。
3. 该行错一个词：在错的词下划一横线，在该行右边横线上写出改正后的词。
Dear student,                                                
Congratulations! We are pleased to telling you that          
you have beaten the high school speaking competition         
about new Tangshan. Your speech was heard by the               
group of five judges, all of who agreed that it was the      
best one in this year. Your family should be proud of        
you! Our office would like to have you to speak in the       
new park, and it will honor those which died in the terrible 
disaster. What you know, this is the day the quake           
happened thirty years before. We invite you to bring         
your family and friends in that special day.                 
1. ________ 
2. ________    
3. ________   
4. ________    
5. ________   
6. ________                                 
7. ________    
8. ________ 
9. ________   
10. ________ 
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单项选择题

为了保障数据的存储和传输安全，需要对一些重要数据进行加密。由于对称密码算法 (17) ，所以特别适合对大量的数据进行加密。国际数据加密算法IDEA的密钥长度是 (18) 位。

A．56

B．64

C．128

D．256
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