数据处理系统主要用于（）的天天重复、变化不大的各种过程处理和事务处理。

A、物理层

B、操作层

C、逻辑层

D、应用层

根据下面的对话情景，在空白处填上一个适当的句子，使对话的意义连贯、完整。

A: Hi, Mark. I called you this morning, but nobody answered. ①______________?

B: I was running at that time. What's up?

A: I want to have a party. ②______________?

B: sure, I'd love to. ③______________?

A: I will have it on Saturday afternoon.

B: Did you tell Mr Lee about it?

A: Yes, I did.

B: ④______________?

A: I plannted to have it today after class. He said there would be a test the day after tomorrow. 

    And he asked me to have it on Saturday afternoon.

B: ⑤______________. See you then.

A: See you then.