用所给动词的适当形式完成对话:
Eve: Where _______(be) you when the UFO _______ (arrive) yesterday?
Joe: I ______(walk) to the post office.
Eve: What did you _______ (see)?
Joe: Well, the UFO _______ (land) right in the middle of the street.
Eoe: What _______ (happen) next?
Joe: One alien ________ (get) out of the UFO and _______(go) into the post office. Eve: Then what did you ________ (do)?
Joe: While the alien ________(buy) stamps, I called the news reporters.