1.The fire caused by an electrical problem didwerehadwas2 it raining when you left your office this afternoon? werehadwasdid3.How many times your travel documents checked before you boarded the airplane? werewashad4.The police located the art work which been stolen from the gallery hadweredidwas5.The employees informed last night that their company was going into receivership.hadweredidwas6.The flight delayed because of bad weather. werewashaddid7.I forgotten to set my alarm clock, so I was late for my train.hadwasdidwere8 you do much sightseeing when you were on vacation in Madrid? WereDidHadWas9.She was surprised that he knew her name. She never met him before.hadwasdidwere10.They leaving for the airport when I last saw them werewasdidhad​

1. The fire was caused by an electrical problem.
Explanation: "was" is the correct answer because it is the past tense form of the verb "to be" and is used to describe the state or condition of something in the past.

2. Was it raining when you left your office this afternoon?
Explanation: "was" is the correct answer because it is the past tense form of the verb "to be" and is used to ask about the state or condition of something in the past.

3. How many times were your travel documents checked before you boarded the airplane?
Explanation: "were" is the correct answer because it is the past tense form of the verb "to be" and is used to describe the state or condition of something in the past.

4. The police located the artwork which had been stolen from the gallery.
Explanation: "had" is the correct answer because it is the past perfect tense of the verb "to have" and is used to describe an action that was completed before another past action.

5. The employees were informed last night that their company was going into receivership.
Explanation: "were" is the correct answer because it is the past tense form of the verb "to be" and is used to describe the state or condition of something in the past.

6. The flight was delayed because of bad weather.
Explanation: "was" is the correct answer because it is the past tense form of the verb "to be" and is used to describe the state or condition of something in the past.

7. I forgot to set my alarm clock, so I was late for my train.
Explanation: "was" is the correct answer because it is the past tense form of the verb "to be" and is used to describe the state or condition of something in the past.

8. Did you do much sightseeing when you were on vacation in Madrid?
Explanation: "did" is the correct answer because it is the past tense form of the auxiliary verb "to do" used to form questions and negatives in the past simple tense.

9. She was surprised that he knew her name. She had never met him before.
Explanation: "had" is the correct answer because it is the past perfect tense of the verb "to have" and is used to describe an action that was completed before another past action.

10. They were leaving for the airport when I last saw them.
Explanation: "were" is the correct answer because it is the past tense form of the verb "to be" and is used to describe the state or condition of something in the past.