根据情景. 填入恰当的句子补全对话。

A:What beautiful shells! Are they yours?

B:Yes, they are.

A:1.                          

B:When I was six years old.

A:2.                                

B:For eight hours.

A:3.                            

B:About 200.

A:Wow! So many!  4.                                    

B:The one that looks like a dog. I like it best. It's very beautiful. And my uncle gave it to me for my

   birthday.

A:Can I have a look?

B:5.             . Here you are.

如图所示，A、B两物体叠放在一起，以相同的初速度上抛（不计空气阻力）。下列说法正确的是

A.在上升和下降过程中A对B的压力一定为零

B.上升过程中A对B的压力大于A物体受到的重力

C.下降过程中A对B的压力大于A物体受到的重力

D.在上升和下降过程中A对B的压力等于A物体受到的重力