摘要：
答案： select sname from s where not exists (select * from c where teacher = '程军' and not exists (select * from sc where c.cno = sc.cno and sc.sno = s 阅读全文
摘要：
It is very hard to wash and especially to dry clothes in winter. But Jane is a very smart girl. She is not afraid of this boring process. Jane has dec 阅读全文