I was sleeping when the UFO arrived

I was sleeping when the UFO arrived .I was sleeping last night when the UFO l_______. when the UFO arrived, I was in the library. he were sleeping when the UFO arrived.为什么用were I was shapping when the UFO arrived(对I was shapping 提问) -Where were you when the UFO arrived?-I was in the( ) -where were you when the UFO arrived?-I was _______ the libr What were you doing when the UFO arrived?和I was walking down I was still sleeping when the fire , He was sleeping late when it arrived When the UFO(landed/was landing),the dog (slept/was sleeping 直接引语变间接引语She said:"I was shopping when the UFO arrived."怎么变间