Complete the sentences with the Past Simple or Past Continuous form of the verbs She WATCH а documentary when she HEAR
 knocking on the door.
Sandra FIND an old ring while she DIG  the weeds in her parents' garden.
Thomas STAND on the deck of the ship when he SEE the whale.
We WORK  on our research paper when the computer suddenly BREAK down.
The tour guide TELL  us about the old church when the alarm RING .
The young man DRIVE  to work when two people in black uniforms STOP him.​

She was WATCHING a documentary when she HEARD knocking on the door.
Explanation: In this sentence, we use the past continuous tense "was watching" to describe an ongoing action in the past, and the past simple tense "heard" to describe a completed action.

Sandra found an old ring while she was DIGGING the weeds in her parents' garden.
Explanation: In this sentence, we use the past simple tense "found" to describe a completed action, and the past continuous tense "was digging" to describe an ongoing action in the past.

Thomas was STANDING on the deck of the ship when he SAW the whale.
Explanation: In this sentence, we use the past continuous tense "was standing" to describe an ongoing action in the past, and the past simple tense "saw" to describe a completed action.

We were WORKING on our research paper when the computer suddenly BROKE down.
Explanation: In this sentence, we use the past continuous tense "were working" to describe an ongoing action in the past, and the past simple tense "broke" to describe a completed action.

The tour guide was TELLING us about the old church when the alarm RANG.
Explanation: In this sentence, we use the past continuous tense "was telling" to describe an ongoing action in the past, and the past simple tense "rang" to describe a completed action.

The young man was DRIVING to work when two people in black uniforms STOPPED him.
Explanation: In this sentence, we use the past continuous tense "was driving" to describe an ongoing action in the past, and the past simple tense "stopped" to describe a completed action.