根据上下文意思，将对话内容补充完整。

A: Look at this picture. ____

B: Yes, it's a picture of the zoo.

A: ____

B: There is a monkey, a panda, a pig and some birds in it.

A: ____

B: The monkey is in the tree.

A: Is there a pig in front of the house?

B: Yes, there is a pig ____ the house. It's playing with the panda.

A: Look at the birds. They can sing well.

B: ____

A: They are in the trees.

B: Oh, the animals are very happy.