简述油脂涂酥的操作工艺。
参考答案:
将动物类药物块或短节,置火上加热,用油脂涂布,加热烘烤,待油脂渗入药内后,再涂再烤,反复操作,直至药物质地酥脆,晾凉或粉碎。
基于"学生-选课-课程"数据库中如下三个关系: S(S#,SNAME,SEX,AGE) SC(S#,C#,GRADE) C(C#,CNAME,TEACHER)
查询选修了课程号为"C2"的学生号和姓名,若用下列SQL的SELECT语句表达时,哪一个是错误的()?
A.SELECT S.S#,SNAME FROM S WHERE S.S# = (SELECT SC.S# FROM SC WHERE C# = ’’C2’’ )
B.SELECT S.S#,SNAME FROM S,SC WHERE S.S# = SC.S# AND C# = ’’C2’’
C.SELECT S.S#,SNAME FROM S,SC WHERE S.S# = SC.S# AND C# = ’’C2’’ ORDER BY S.S#
D.SELECT S.S#,SNAME FROM S WHERE S.S# IN (SELECT SC.S# FROM SC WHERE C# =’’C2’’ )
政府债券的利率可以视为时间价值。( )