Past Perfect

Respuesta correcta: A) had already left

• A) had already leftCorrect. 'Had already left' shows the train's departure completed before the moment of arrival, which is exactly the past perfect.
• B) was leaving alreadyWrong. 'Was leaving' is the past continuous and would suggest the train was just beginning to depart.
• C) has already leftWrong. 'Has already left' is the present perfect and cannot describe a completed event before a past reference point.
• D) already leftWrong. 'Already left' states the departure but gives no information about its position relative to the arrival.

Respuesta correcta: B) had finished

• A) has finishedWrong. 'Has finished' is the present perfect and refers to a period leading to the present.
• B) had finishedCorrect. The past perfect is formed with 'had' plus the past participle, giving 'had finished'.
• C) had finishWrong. After 'had' the verb must be the past participle, so a bare 'finish' is not correct.
• D) was finishingWrong. 'Was finishing' is the past continuous and describes an action in progress, not a completed one.

Respuesta correcta: C) By the time the ambulance arrived, the driver had already called for help.

• A) By the time the ambulance arrived, the driver has already called for help.Wrong. 'Has already called' is the present perfect, which cannot sit before a past reference point.
• B) By the time the ambulance arrived, the driver already called for help.Wrong. 'Already called' shows the sequence but omits the perfect aspect that the construction normally requires.
• C) By the time the ambulance arrived, the driver had already called for help.Correct. 'By the time' introduces a past reference point, and the past perfect marks the call as completed before it.
• D) By the time the ambulance arrives, the driver had already called for help.Wrong. 'Arrives' is present tense and destroys the past time frame that the past perfect requires.

Respuesta correcta: D) She hadn't finished the report before the deadline.

• A) She not had finished the report before the deadline.Wrong. 'Not' cannot precede the auxiliary in standard English word order.
• B) She hadn't finishing the report before the deadline.Wrong. 'Hadn't finishing' uses a gerund where the past participle is required.
• C) She didn't finish the report before the deadline.Wrong. 'Didn't finish' is a negative past simple, which reports the outcome rather than the earlier state.
• D) She hadn't finished the report before the deadline.Correct. Negating the auxiliary 'had' produces the negative past perfect and keeps the past participle in place.

Respuesta correcta: A) Had you ever visited Paris before that trip?

• A) Had you ever visited Paris before that trip?Correct. The auxiliary 'had' inverts to the front of the question and the past participle follows the subject.
• B) You had ever visited Paris before that trip?Wrong. This is a statement, and it lacks the inversion required by a yes/no question.
• C) Have you ever visited Paris before that trip?Wrong. 'Have visited' is the present perfect and asks about experience up to the present moment.
• D) Did you ever visit Paris before that trip?Wrong. 'Did visit' asks about a single past trip rather than about a prior experience before a later event.

Respuesta correcta: B) He had lost his keys, so he couldn't get into the flat.

• A) He lost his keys, so he couldn't get into the flat.Wrong. 'Lost' states the loss but leaves the causal priority to the reader to infer rather than marking it grammatically.
• B) He had lost his keys, so he couldn't get into the flat.Correct. The past perfect places the loss before the later attempt to open the door, which is the intended order of events.
• C) He was losing his keys, so he couldn't get into the flat.Wrong. 'Was losing' is the past continuous and describes an ongoing loss, which is not the intended sense.
• D) He has lost his keys, so he couldn't get into the flat.Wrong. 'Has lost' is the present perfect and would connect the loss to the present rather than to an earlier past moment.

Respuesta correcta: C) By 2019 the team had completed three studies, and in 2021 it published a synthesis.

• A) By 2019 the team had completed three studies, and in 2021 it publishes a synthesis.Wrong. 'It publishes' is present tense and breaks the narration anchored in past years.
• B) By 2019 the team has completed three studies, and in 2021 it published a synthesis.Wrong. 'Has completed' is the present perfect and cannot belong to a past reference point such as 2019.
• C) By 2019 the team had completed three studies, and in 2021 it published a synthesis.Correct. The past perfect marks the studies as finished by 2019, and the later event in 2021 uses the past simple, which preserves the sequence.
• D) By 2019 the team completed three studies, and in 2021 it published a synthesis.Wrong. 'Completed' in the simple past leaves the priority of the two years ambiguous without the perfect aspect.

Respuesta correcta: D) She had studied in Arequipa for two years before she moved abroad.

• A) She studied in Arequipa for two years before she will move abroad.Wrong. 'Will move' is future tense and cannot serve as the later past event that anchors the past perfect.
• B) She had studied in Arequipa for two years since she moved abroad.Wrong. 'Since' marks a starting point that continues, which contradicts the completed period described.
• C) She has studied in Arequipa for two years before she moved abroad.Wrong. 'Has studied' is the present perfect and would extend the period of study up to the present.
• D) She had studied in Arequipa for two years before she moved abroad.Correct. 'Had studied for two years' presents the period of study as over before the move took place.

Respuesta correcta: A) When the storm arrived, we hadn't yet reached the summit.

• A) When the storm arrived, we hadn't yet reached the summit.Correct. 'Hadn't yet' reports that the climb was still incomplete at the moment the storm arrived.
• B) When the storm arrived, we not yet reached the summit.Wrong. 'Not yet' requires the auxiliary 'had' in front of it in a past perfect construction.
• C) When the storm arrives, we hadn't yet reached the summit.Wrong. 'Arrives' is present tense, so the sentence mixes present and past time reference.
• D) When the storm arrived, we haven't yet reached the summit.Wrong. 'Haven't' is the present perfect and would place the incompleteness in the present.

Respuesta correcta: B) The project had been delayed for a year before the funding finally arrived.

• A) The project has been delayed for a year before the funding finally arrived.Wrong. 'Has been delayed' is the present perfect continuous and extends the delay to the present.
• B) The project had been delayed for a year before the funding finally arrived.Correct. The past perfect continuous presents the delay as a process that continued right up to the moment the funding arrived.
• C) The project had delayed for a year before the funding finally arrived.Wrong. 'Had delayed' is missing the second participle that the perfect continuous requires.
• D) The project was delayed for a year before the funding finally arrived.Wrong. 'Was delayed' marks the delay as a bounded event rather than as a continuing process up to that point.

Respuesta correcta: C) The garden looked empty because the gardeners had left an hour earlier.

• A) The garden looked empty because the gardeners have left an hour earlier.Wrong. 'Have left' is the present perfect and cannot be combined with 'an hour earlier'.
• B) The garden looked empty because the gardeners left an hour earlier.Wrong. 'Left' leaves the timing ambiguous and can suggest the departure happened at the moment of observation.
• C) The garden looked empty because the gardeners had left an hour earlier.Correct. 'Had left' places the departure before the observation, which explains the empty garden observed in the past.
• D) The garden looked empty because the gardeners had leaving an hour earlier.Wrong. 'Had leaving' is not a valid form; the past perfect requires the past participle.

Respuesta correcta: D) He had been living in Cusco for a decade when his sister called him.

• A) He had lives in Cusco for a decade when his sister called him.Wrong. 'Had lives' is not a valid form, since 'had' requires the past participle and the continuous adds another -ing.
• B) He had living in Cusco for a decade when his sister called him.Wrong. 'Had living' lacks the second participle that the perfect continuous requires.
• C) He had lived in Cusco for a decade when his sister called him.Wrong. 'Had lived' is not incorrect in English, but it presents a state rather than the ongoing process the duration phrase suggests.
• D) He had been living in Cusco for a decade when his sister called him.Correct. With a duration ending at a past point, the continuous form is the natural and fully grammatical choice.

Respuesta correcta: A) After she had left, the phone rang.

• A) After she had left, the phone rang.Correct. 'After' plus the past perfect presents an earlier completed event as the starting point of the following one.
• B) After she did left, the phone rang.Wrong. 'Did left' double-marks the past and is not a correct auxiliary combination.
• C) After she had leaving, the phone rang.Wrong. 'Had leaving' is not a valid clause; after 'had' the past participle is required.
• D) After she has left, the phone rang.Wrong. 'After she has left' uses the present perfect, which would place the leaving close to the present moment.

Respuesta correcta: B) Yes, I had.

• A) Yes, I have.Wrong. 'Yes, I have' answers a present perfect question, not a past perfect one.
• B) Yes, I had.Correct. A short answer contains only the pronoun and the auxiliary, and the auxiliary must match the tense of the question.
• C) Yes, I did.Wrong. 'Yes, I did' is the short answer used with the past simple, not with the past perfect.
• D) Yes, I had met.Wrong. Including the participle 'met' in a short answer is not standard; the auxiliary is sufficient.

Respuesta correcta: C) He had known her for years before they became friends.

• A) He had know her for years before they became friends.Wrong. 'Had know' is not a valid form; after 'had' the past participle 'known' is required.
• B) He had been knowing her for years before they became friends.Wrong. 'Had been knowing' is ungrammatical because stative verbs resist the continuous form.
• C) He had known her for years before they became friends.Correct. 'Know' is a state verb and does not normally take the progressive, so the past perfect is used instead.
• D) He had been know her for years before they became friends.Wrong. 'Had been know' combines a passive auxiliary with a base form and is not a correct structure.

Respuesta correcta: D) Because she had forgotten her umbrella, her phone got soaked.

• A) Because she had forgetting her umbrella, her phone got soaked.Wrong. 'Had forgetting' is not a valid form and cannot open this causal clause.
• B) Because she forgot her umbrella, her phone got soaked.Wrong. 'Forgot' leaves the order of the two events unmarked, which can make the cause ambiguous.
• C) Because she has forgotten her umbrella, her phone got soaked.Wrong. 'Has forgotten' is the present perfect and connects the forgetting to the present moment.
• D) Because she had forgotten her umbrella, her phone got soaked.Correct. 'Because she had forgotten' presents the forgetting as complete before the phone got soaked, which matches the causal reading.

Respuesta correcta: A) The second sentence makes the earlier completion explicit, so the listener cannot read the two actions as simultaneous or unordered.

• A) The second sentence makes the earlier completion explicit, so the listener cannot read the two actions as simultaneous or unordered.Correct. This describes the informational contribution of the past perfect accurately, namely the explicit marking of prior completion.
• B) The first sentence is wrong because the past perfect requires a specific time expression.Wrong. The past perfect does not require a time expression; it can be introduced by a conjunction or stand alone.
• C) The two sentences mean exactly the same, since aspect does not change meaning in English.Wrong. Aspect does change meaning here, since the two sentences differ in whether the order of events is recoverable from the sentence itself.
• D) The second sentence is wrong because the past simple is always needed before another past clause.Wrong. The past simple is perfectly acceptable before another past clause; the past perfect adds priority rather than being mandatory.

Respuesta correcta: B) The sensor had failed twice before the maintenance team replaced it.

• A) The sensor has failed twice before the maintenance team replaced it.Wrong. 'Has failed' is the present perfect and cannot precede a past simple main clause in this sense.
• B) The sensor had failed twice before the maintenance team replaced it.Correct. The past perfect records the two earlier failures before the replacement, and the replacement itself is correctly in the past simple.
• C) The sensor was failing twice before the maintenance team replaced it.Wrong. 'Was failing' is the past continuous, which marks an ongoing process rather than two separate completed failures.
• D) The sensor fails twice before the maintenance team replaced it.Wrong. 'Fails' is present simple and contradicts the past frame of the second clause.

Respuesta correcta: C) He said that he had finished, but the report showed that he was still working.

• A) He said that he had finish, but the report showed that he is still working.Wrong. 'Had finish' lacks the participle and 'is still working' breaks the past time frame.
• B) He said that he has finished, but the report showed that he was still working.Wrong. 'Has finished' is the present perfect and cannot sit inside a 'he said' clause about the past.
• C) He said that he had finished, but the report showed that he was still working.Correct. 'Had finished' reports the earlier completed state, 'said' anchors the narration in the past and 'was still working' shows the contrast at that moment.
• D) He said that he finished, but the report showed that he is still working.Wrong. Both 'finished' and 'is still working' belong to different time frames, so the contrast is lost.

Respuesta correcta: D) The village had recovered from the flood long before the new bridge was opened.

• A) The village had recovering from the flood long before the new bridge was opened.Wrong. 'Had recovering' is not a valid form; the past perfect requires the past participle after the auxiliary.
• B) The village had recovered from the flood long before the new bridge is opened.Wrong. 'Is opened' is present passive and does not match the past time frame of the sentence.
• C) The village has recovered from the flood long before the new bridge was opened.Wrong. 'Has recovered' is the present perfect, which links past and present and cannot precede a past simple clause here.
• D) The village had recovered from the flood long before the new bridge was opened.Correct. The recovery is presented as complete well before the bridge opening, and both events sit in the past.