Answer: D) By the time the vaccine was found, everybody had been a zombie.
Explanation for this question is being written.
Answer: B) Past perfect tense.
Answer: A) Had never been, went.
Answer: A) Had left, arrived.
Answer: A) Was, had eaten.
Answer: D) D
Answer: A) Had gone.
Answer: A) Had answered, received.
Answer: A) Had known / met.
Answer: A) Before
Answer: A) Would have paid for.
Answer: D) Reached / had sold.
Answer: B) Had spent, asked.
Answer: A) Had been; began.
Answer: B) When the event in the that clause happened before the event in the main clause.
Answer: A) She had finished her homework before she went to the party.
Answer: A) Had seen/ knew.
Answer: A) Came / had left.
Answer: A) Arrived/had finished.
Answer: B) BEFORE
Answer: B) Was, had cleaned.
Answer: A) Had just entered / opened-entered.
Answer: A) Caught
Answer: A) Arrived/ had left.
Answer: A) Had left.
Answer: B) Had
Answer: A) Past Perfect.
Answer: B) Was delayed.
Answer: A) Had lived / went.
Answer: A) Past Simple, Past Perfect.
Answer: B) It was destroyed.
Answer: B) Past Perfect.
Answer: B) Had left.
Answer: B) Asked/hadn't done.
Answer: C) Before, after, by the time.
Answer: D) Had completed/ flew.
Answer: A) Was staying.
Answer: C) Applied / would get.
Answer: A) Before they washed the dishes.
Answer: C) Came
Answer: A) Received
Answer: C) Tells us the order in which actions or events occur.
Answer: B) Had / eaten.
Answer: B) Destroyed / had built.
Answer: C) Had heard, began.
Answer: C) Had been.
Answer: B) Had finished, played.
Answer: B) Past Perfect Tense.
Answer: C) Hadn't eaten / already had.
Answer: B) Didn't recognise, had changed.
Answer: A) The ground was wet because it had rained all night.
Answer: A) Had answered, entered.
Answer: B) Had told.
Answer: A) Past Simple is used for actions that happened at a specific time in the past; Present Perfect is used for actions that have relevance to the present.
Answer: A) Gone
Answer: A) Moved
Answer: A) Broke
Answer: A) Past Perfect Tense.
Answer: A) Had gone-became.
Answer: B) False