补全对话。

A: Morning! What can I do for you?

B: We'd like to make a trip for a weekend holiday,please.

A: There are many travel paths.1______?

B: We'd like to choose Jinggang mountains.

A: It's really worth visiting. 2______?

B: We're not sure.Which hotel do you think is comfortable?

A: The Holiday Home is very good.What's more important,3.

B: We don't want to live in an expensive hotel.That's what we'll do.

A: 4______?

B: OK. I'll ask my wife to fill in this form.By the way,is it all right if we pay by credit card (信用卡)?

A: 5.______ Enjoy your weekend.

B: Thank you.

下列哪一种生物不是由一个细胞构成的（　　）

A．酵母菌

B．海带

C．草履虫

D．变形虫