一个多用户的应用系统通常有用户管理功能，允许增加新的用户。用户信息一般包括用户名，假设规定用户名必须是以字母开头的、不超过8个字符的字母数字串，那么，下面哪组值均属于用户名的无效等价类______。
A. li111111，G1enford Myers，1238123
B. Lin-Yie，Lin-feng，空值，linyifei
C. lin-yifei，空值，Myers G．，genford
D. lin-yifei，lin-fen，a111111，genford
查看答案
通过关联关键字“系别”这一相同字段，如图所示的表二和表一构成的关系为
A. 一对一
B. 多对一
C. 一对多
D. 多对多
Which of the following statements is TRUE？
A. Shyness helps us to live up to our full potential．
B. Shyness enables us to understand ourselves better．
C. Shyness blocks our chances to a rich life
D. Shyness has nothing to do with lack of self-esteem．
How do the shy people respond to praise？
A. They feel happy about it．
B. They feel it is not true．
C. They feel it confirms their inferiority
D. They are very sensitive to it．
The best title for this passage would be______．
A. Hints for Successful Reading
B. Hints for Speeding Reading
C. Effective Reading
D. Lightning Speed Exercises
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