已知关系模式：
学生关系S（SNO，SNAME）。SNO为学号，SNAME为姓名。
课程关系C（CNO，CNAME，CTEACHER）。CNO为课程号，CNAME为课程名，CTEACHER为任课教师。
选课关系SC（SNO，CNO，SCGRADE）。SCGRADE为成绩。
写出没有选修过“李明”老师讲授课程的所有学生姓名的SQL语句。
参考答案：
Select SNAME FROM S
Where NOT EXISTS(
Select*FROM SC, C
Where SC. CNO=C. CNO
AND CNAME=’李明’
AND SC. SNO=S. SNO)
| 完形填空。 | |||
| Sports in America In many parts of the world, there are four seasons: spring, summer, fall and winter. In the USA, there are only three: football, basketball and baseball. If you want to know 1 , just have a look at what people are playing. Sports are an important part of American culture. Throughout their school 2 , Americans learn to play many sports. All students take P.E. classes in school. Some try out for the school teams, 3 others join school sports leagues. For many people in the USA, sports are not just 4 . They're almost a religion (宗教). 5 sports fans buy expensive tickets to watch their favorite teams and athletes 6 in person. Other fans watch games at home, glued to their TV sets. The most devoted (投入的) sports fans 7 a game. | |||
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