the past continuous
noun [ S ] uk/ˌpɑːst kənˈtɪn.ju.əs/ us/ˌpæst kənˈtɪn.ju.əs/ (also the past progressive)
过去进行时
the grammatical form used for an action that someone was doing or an event that was happening at a particular time. It is made with "was" or "were" and the -ing form of a verb.
"I was cooking" is an example of the past continuous. I was cooking 是过去进行时的一个例子。