在分布式数据库系统中，（    ）是指用户或应用程序无需知道局部使用的是哪种数据模型。

(单选题)( ) enough time and money, the researchers would have bee (单选题)( ) no cause for alarm, the old man went back to his room (单选题)See the clouds! It ( ) rain! (单选题)I ( ) writing the paper as scheduled, but my mother's ill (单选题)The student said there were a few points in the essay he ( (单选题)Nowadays a lot of adults go to evening schools ( ) furthe (单选题)If you really have to leave during the meeting, you'd better (单选题)To my horror, I saw, ( ) my father's shoulder, a gorilla. (单选题)I think you can take a(n) ( ) language course to improve (单选题)With ( ) exceptions, the former president does not appear