What is the Glasgow’s top attraction（）
A. The John Rylands Library
B. National Football Museum
City Town Hall
D. Burrell Collection
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在学生选课数据库中，查询平均成绩大于等于60分的同学，SQL语句为（）
A. SELECT Sno, AVG（Grade） FROM SC GROUP BY Sno HAVING AVG（Grade）＞=60;
B. SELECT Sno FROM SC WHERE Grade＞=60 GROUP BY Sno;
C. SELECT Sno, Grade FROM SC GROUP BY Sno HAVING AVG（Grade）＞=60;
D. SELECT Sno FROM SC GROUP BY Sno HAVING Grade ＞=60;
下列选项中哪一个是正确的空值查询条件的SQL表达（）
A. ＜ ＞NULL
B. !=NULL
C. IS NOT NULL
D. NOT IS NULL
检索选修了课程”C1”的学生中成绩最高的学生的学号，正确的SELECT语句为（）
A. SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE ＞=ALL （SELECT Grade FROM SC WHERE Cno=’C1’）
B. SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE IN （SELECT Grade FROM SC WHERE Cno=’C1’）
C. SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE ＞ ANY （SELECT Grade FROM SC WHERE Cno=’C1’）
D. SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE ＞= （SELECT Grade FROM SC WHERE Cno=’C1’）
After using reagents in chemical lab, you should to（）
A. put it back in place immediatel
B. put it in an easy accessing place
C. make up by yourself,when it is insufficient
D. keep the bottle open for easy use next time
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