Answer: B) Had already eaten.
Explanation for this question is being written.
Answer: A) Hadn't saved.
Answer: A) Had left.
Answer: B) Had never seen.
Answer: D) Had written.
Answer: A) True
Answer: B) Had finished.
Answer: B) Had/closed
Answer: B) She had finished.
Answer: C) Had forgotten.
Answer: A) Had studied.
Answer: B) Had found.
Answer: A) Had lost.
Answer: C) Had finished.
Answer: B) Had read.
Answer: A) Had they fed.
Answer: A) Had destroyed, ended.
Answer: B) Had just bought.
Answer: A) The train had left.
Answer: B) Had taken.
Answer: A) Had
Answer: A) Had already started.
Answer: B) The train had left.
Answer: A) Past perfect.
Answer: B) Had gone.
Answer: A) Had already left.
Answer: A) Had finished.
Answer: D) Had known.
Answer: A) Had started.
Answer: A) Had ended.
Answer: B) HAD LEFT.
Answer: B) Had had.
Answer: A) Had appeared.
Answer: D) Had
Answer: C) Past Perfect Tense (Passive Voice).
Answer: A) Yes
Answer: A) Had written.
Answer: D) They'd never flown.
Answer: C) Had
Answer: A) Andres had been a good student.
Answer: C) Had already packed.
Answer: C) Had already started.
Answer: A) Studied
Answer: A) We washed our face after we had brushed our teeth.
Answer: A) Had been blocked.
Answer: B) Had left.
Answer: C) Had had went.
Answer: C) Had already set.
Answer: D) Had left.
Answer: C) Had left.
Answer: A) Had / gone.
Answer: C) Had sold out.
Answer: B) Went, had switched.
Answer: A) Had seen.
Answer: B) Had made.
Answer: D) Had seen.