What were you doing when the UFO arrived
Go for it
Unit 3 Have you ever seen them
UFO (Unidentified Flying Objects) 不明飞行物;飞碟 UFO : Unidentified Flying Object 不明飞行物• 1947 年 6 月 24 日,一名叫做阿诺德的美国商人,架着一架小型飞机在华盛顿州上空,发现一组巨型不明飞行物以 1000 公里左右的速度,同他一起在空中翱翔
阿诺德的有关目击报告第一次引起公众的兴趣,从此“飞碟”或 UFO 便迅速流传开来
alien外星人 UFO: Undentified Flying ObjectWhere can we see them
RevisionWhat are they doing
They are running
What is he doing
He is playing tennis
What is the man doing
He is eating
I am writing on the blackboard
I am walking in the room
What were you doing when he came in
I was writing on the blackboard when he came in
I was walking in the room when he came in
含义: 表示现在 正在进行的动作
结构: is/am/are + doing例句: I am having an English class含义 : 表示过去某个时刻 正在进行的动作
结构: was/were + doing例句: I was having an English clas