关系数据库的查询语言是一种( )语言

医疗机构因临床急需进口少量药品,应向国务院药品监督管理部门提出申请,并持有E.桌子上有光盘15张,其中音乐光盘6张、电影光盘6张、游戏光盘3张,从中任取3张,其中恰好有音乐、电影、游戏光盘各1张的概率是多少?听力原文: One winter day in 1891, a class at the training school in Massachusetts, USA, went into the gym for their daily exercises. Since the football season had ended, most of the young man felt they were in for a boring time. But their teacher James Nasmyth had other ideas. He had been working for a long time on a new game that would have the excitement of American football. Nasmyth showed the men a basket he had hung at each end of the gym and explained that they were going to use around European football At first, everybody try to throw ball into the basket no matter where he was standing .Pass ! Pass! Nasmyth kept shouting, blowing his whistle to stop the excited players. Slowly, they began to understand what was wanted of them. The problem with the new game, which was soon called basketball, was getting the ball out of the basket. They used ordinary fruit baskets with bottoms, and the ball, of course, stayed inside. At first, someone had to clime up every time a basket was scored. It was several years before someone came up with the idea of removing the bottom of the basket and letting the ball fall through. There have been many changes in the rules since then and basketball has become one of the world's most popular sports.。