根据下面对话中的情景，在空白处填入适当的语句，使对话内容完整。

(Jenny and Nancy meet on the street. ) 

J=Jenny；N=Nancy

J: Hello,Nancy.  1  

N: Fine, thanks,Jenny. 

J: I heard you went somewhere for vacation. 

  2  

N: Well,I have been to Hainan Island with my cousins. There are too many exciting things there,especially diving(潜水)in the real sea!

J:   3    My parents and I will go there , too. What should we take?

N: A camera,sunglasses,umbrellas and some cool clothes.

J: OK,thank you.  4  

N: You can get there by plane. Because It's too far away.  5  

J: Thank you! I think we sure will !

同温同压下，已知O₂的密度为ρ g/L，则NH₃的密度为（　　）

A．

B．

C．

D．