根据对话内容，在空白处填写适当的话语(话语可能是一个句子，也可能是一个短语或一个词)

A: The summer vacation is coming. (1)__________?

B: Well, I'm going to work in McDonald's this summer.

A: Really? Why?

B: You know I can't afford to have a trip every year, so I really want to (2)__________ for the next school trip.

A: Sounds like a good idea. (3)__________?

B: Yes, I worked there last year. How about you?

A: I'm going to trek through the Amazon jungle.

B: Oh, my god! Isn't it supposed to be (4)__________?

A: Yes, it is. But it's thrilling.

B: I agree. (5)__________!

A: Thanks.

在数据库技术中，实体—联系模型是一种

A．概念数据模型

B．结构数据模型

C．物理数据模型

D．逻辑数据模型