a/an + 文具名词 — 英语情景题

放学后，Tom在书包里找文具。请选择a或an填空，完成对话。 Tom: Mum, I can't find my school things. Mum: What do you need, Tom? Tom: I need (1)________ eraser and (2)________ pen. Mum: Here is (3)________ ruler, too. Is it yours? Tom: Yes! And look, this is (4)________ pencil. It's new. Mum: Put them in your bag, or you will lose them again.