备战2021年高考英语——时态之过去进行时（一）
过去进行时（Past continous tense）：表示过去某时正在进行的动作(不强调是否完成）。主要用法是描述一件事发生的背景；一个长动作发生的时候，另一个短动作发生。
结构：was/were+doing
When my husband was going into the dining room this morning, he dropped some coins on the floor.
Their father was watching TV while they were having dinner.
★变疑问句将be动词移到句首
Was their father watching TV while they were having dinner.
★变否定句在be动词后面加 not
Their father was not watching TV while they were having dinner.
