They——to enter the building by the back door； howerve,the fr

They——to enter the building by the back door； howerve,the fr they __to enter the building by the back door:however,the fr Please enter the house by the back door. I enter the building ____ the side door. They're____knocking at the back door(尝试) they are ____koocking at the back door they didn’t discover until the happened to enter the back ro the door to the outside of the building什么意思? He entered the building by a side door. Look!The_(enter)to the building is over there by the back door中by的意思 1、They went the back door into the garden.