Answer :
This exercise is about using the correct form of verbs in a sentence. It centers on the past continuous and simple past tenses, which are often used together in sentences to show actions happening one after another or to provide background information.
While I (wait) was waiting for the bus, I (see) saw an old friend.
- Here, 'was waiting' is past continuous to describe the ongoing action, and 'saw' is simple past for the action that happened.
Mary (drop) dropped her keys while she (run) was running to catch the train.
- 'Dropped' is in the simple past, and 'was running' describes the action Mary was in the middle of doing.
I (not listen) wasn't listening when the teacher (ask) asked me a question.
- 'Wasn't listening' shows the action in progress, and 'asked' is the completed action.
The baby (cry) was crying while her mother (cook) was cooking lunch.
- Both 'was crying' and 'was cooking' are in the past continuous tense, showing simultaneous ongoing actions.
John (have) was having a shower when the phone (ring) rang.
- 'Was having' is the continuous action, while 'rang' is the sudden event.
While we (walk) were walking through the park, it (start) started to rain.
- 'Were walking' is the ongoing action, and 'started' marks the sudden event.
I (look) was looking out the window when I (notice) noticed a fire in the building opposite.
- 'Was looking' gives background information, while 'noticed' is the main past action.
She (break) broke her leg while she (ski) was skiing in the Alps.
- 'Broke' is the sudden action, and 'was skiing' provides the context.
My friends (not pay) weren't paying attention while the teacher (explain) was explaining the rules.
- 'Weren't paying' is the continuous action, and 'was explaining' describes the event happening at the same time.
While he (drive) was driving to work, he (see) saw an accident.
- 'Was driving' indicates the action in progress, and 'saw' describes the completed action.
We (have) were having dinner when our guests (arrive) arrived.
- 'Were having' is the continuous action, while 'arrived' indicates sudden action.
I (see) saw a famous actor while I (shop) was shopping in the mall.
- 'Saw' is the simple past action, and 'was shopping' gives the setting.
They (not hear) didn't hear the alarm because they (sleep) were sleeping.
- 'Didn't hear' shows inability due to 'were sleeping', both in the past.
What (you/do) were you doing when the electricity (go) went out last night?
- 'Were you doing' sets the ongoing action, and 'went out' is the event that interrupted it.
When I (open) opened the door, the dog (run) ran out of the house.
- 'Opened' and 'ran' are both simple past for sequential actions.
While I (paint) was painting the wall, my brother (fix) was fixing the door.
- Both actions, 'was painting' and 'was fixing', are simultaneous and ongoing.
She (feel) felt nervous because everyone (look) was looking at her.
- 'Felt' is the reaction in simple past, and 'was looking' is the ongoing reason.
The students (discuss) were discussing the answers when the teacher (come) came in.
- 'Were discussing' is the background action, and 'came in' happens suddenly.
He (fall) fell asleep while he (read) was reading the newspaper.
- 'Fell' shows the sudden past action, while 'was reading' was the ongoing action.
We (not go) didn't go outside because it (rain) was raining heavily.
- 'Didn't go' is the result, with 'was raining' providing the justification.
