過去進行時是表示過去某一時刻或某一時間內正在進行或發生的動作。可以從兩個方面來理解：1 過去某一時刻正在進行或發生的動作。E．g． They were playing football at ten o’clock yesterday morning． My mother was cooking when I got home． I was washing my clothes at this time yesterday． 2 過去某階段持續進行的動作 What were you doing during the holiday? 另外，在復合句中，若主要動作和背景動作是同時發生的，那么主從句都可用過去進行時e．g． Jenny was reading while Danny was writing．

　　其結構是助動詞be的過去形式was/were ＋v－ing．

　　其句式變化仍然要在be上做文章。E．g． We were working in class．

　　We weren’t working in class． Were you working in class?

　　過去進行時常與過去某一特定時間的狀語連用，如 last night， at that time， at noon yesterday， last Sunday 等。 也有時沒有時間狀語，要通過上下文的暗示來確定用過去進行時。E．g． The students all worked hard． Everyone knew what he was working for．

　　做題時常見錯誤如下：

一、易把be＋現在分詞記成be＋過去分詞

　　例：He was talked （talk） to his mum at that time．

　　答案：was talking

　　解析：過去進行時與現在進行時結構上的區別體現在be動詞上。

二、丟掉be動詞或忘記把動詞變成現在分詞

　　例：1 I watching （watch） TV when he came in．

　　2 They were play （play） games at 5：00 p．m． yesterday．

　　答案：1 was watching 2 were playing

　　解析：現在進行時中“be＋現在分詞，缺一不可”的規律也可應用于過去進行時。

三、對動詞或動詞詞組提問時丟掉doing

　　例：We were flying kites at 5：00 p．m． yesterday． （對劃線部分提問）

　　What were you at 5：00 p．m． yesterday?

　　答案：What were you doing at 5：00 p．m． yesterday?

　　解析：現在進行時中“What……doing……”?句式同樣適用于過去進行時。