要表达过去某个时刻正在进行的动作，用 was / were + -ing 动词。I、he、she、it 用 was；you、we、they 用 were。
was / were + -ing
At 8pm I was watching TV.
She was cooking dinner.
They were playing in the garden.
Not "They was playing in the garden." — say "They were playing in the garden.". they 要用 were，不用 was。
试一试: At 8pm, we ___ dinner. (were having / was having / were have) 答案: were having — we 用 were，动词加 -ing：were having。"Was having" 是用于单数人称（I/he/she）的，"were have" 又漏掉了 -ing。
Not "She was driveing to work." — say "She was driving to work.". 加 -ing 前要去掉不发音的 e：drive → driving，不是 driveing。
试一试: At noon, they were ___ lunch. (have) (having / haveing / haved) 答案: having — 加 -ing 前去掉不发音的 e：have → having。"Haveing" 错在保留了 e，"haved" 不是真实存在的形式。
否定和疑问
要说否定，把 not 放在 was/were 后面：wasn't / weren't + -ing。要提问，把 was / were 提到主语前面：Was / Were + 主语 + -ing?
I wasn't sleeping at 10pm.
They weren't listening to me.
Were you waiting for the bus?
Was she working yesterday?
Not "Did you were working?" — say "Were you working?". 提问时把 were 移到这个人前面——不要加 did。
试一试: It was quiet. The children ___ any noise. (not / make) (weren't making / wasn't making / didn't making) 答案: weren't making — The children 是复数，所以用 weren't，并保留 -ing：weren't making。"Wasn't" 是给一个人用的，"didn't making" 把两种过去形式混在一起了。
试一试: ___ you ___ TV when I called? (Were … watching / Did … watching / Was … watching) 答案: Were … watching — 对 you 提问，用 Were 开头并保留 -ing：Were you watching? "Did" 不跟 -ing 搭配，"Was" 是给 I/he/she/it 用的。
一个长动作和一个短动作
当一个短动作打断了一个更长的动作时，长动作用 was / were + -ing，短动作用一般过去式。
I was reading (long) when the phone rang (short).
She was driving when she saw the accident.
They were playing when it started to rain.
试一试: Amina 正在做晚饭，做了好一会儿。突然，门铃响了一声。 哪个符合已经在进行中的较长动作？ (She was cooking dinner. / She cooked dinner.) 答案: She was cooking dinner. — 做饭是已经在进行中的较长动作，所以用 was cooking。"She cooked dinner" 听起来像是已经做完了，不是门铃响起时的背景动作。
试一试: Hiroshi 正在开一段长途车。忽然，就在一瞬间，他看到前面出了事故。 哪个符合在一瞬间发生的短动作？ (He saw an accident. / He was seeing an accident.) 答案: He saw an accident. — 看到事故发生在一瞬间，所以用一般过去式 saw。"Was seeing" 会把它变成一个长动作，但这其实是突然发生的。
while 搭配长动作
While 搭配长动作（was / were + -ing）。When 搭配短动作（一般过去式）。
While I was sleeping, the phone rang.
When the phone rang, I was sleeping.
While she was cooking, someone knocked.
Not "While the phone rang, I was sleeping." — say "While I was sleeping, the phone rang.". While 搭配长动作（was sleeping），不搭配短动作（rang）。
试一试: Mei 看书看了很久。突然打进来的那个电话，是打断她的短动作。 哪个词适合放在长动作 was reading 前面？ (While she was reading, the phone rang. / When she was reading, the phone rang.) 答案: While she was reading, the phone rang. — 看书是长动作，while 搭配长动作：While she was reading, the phone rang。"When" 通常指向短动作（电话响起的那一刻）。
试一试: While Lars ___ home, it ___ to rain. (was walking … started / walked … was starting / was walking … was starting) 答案: was walking … started — 走路回家是长动作 → was walking。下雨这件事是短的瞬间 → started。长动作用 was + -ing，短动作用一般过去式。