完型填空 另外答案上说One day,the doorbell rings and she opened_____the door.opened为什么不用单三

完型填空 另外答案上说One day,the doorbell rings and she opened_____the door.opened为什么不用单三
Mrs Green loves flowers very much and she has a small but beautiful garden.In summer the flowers are very n_______.One day,the doorbell rings and she o______the door.She sees a l________boy outside.He is about seven years old and has a lot of f_____in his hands."I'm selling flowers,"he says,"do you w______any?They're very cheap.I pick t_____this morning.""M______boy,"Mrs Green answers."I have a lot of flowers in my garden.S______I needn't pay for them.""Oh,no,you don't have any flowers in your g________now,"says the boy,"they are all here in my h_______."