动物名词单复数区分 — 英语情景题

情景对话：在动物园门口，Sam 和 Lily 数动物。 Sam: Look! A panda! Lily: Yes. It's (1)________ panda. It's so cute. Sam: Look there! How many birds? Lily: One, two, three! Three birds! Sam: Right. They are three (2)________. Lily: And I see two tigers over there. They are two (3)________. Sam: Great! Let's go and see them!