I came here for nothing else but to see you _____, but an accident (事故) happened _____. [ ]

A. in fact; on purpose

B. according to; on purpose

C. on purpose; by chance

D. on purpose; in chance

在原型法归纳的基本模型结构中，下列哪个结构是完成定期修改数据库的

A．生成报表

B．批量转换

C．成批对接

D．联机查询