4.2 Tenses & Aspects II: Perfect Forms, Sequence of Tenses & Voice
Key Takeaways
- Present perfect links past action to present relevance and is incompatible with finished-time markers such as yesterday, last year, or in 2015.
- 'Since' takes a point in time while 'for' takes a duration — a distinction NTS tests directly in present perfect items.
- Past perfect exists only to show that one past event preceded another past event; with a single past event it is an error, not a refinement.
- In reported speech the sequence-of-tenses rule shifts each verb one step back unless the reported statement is a permanent truth.
- Passive voice is formed with be + past participle and keeps the tense of the original active verb.
Tenses & Aspects II: Perfect Forms, Sequence of Tenses & Voice
The simple and progressive aspects locate an action in time. The perfect aspect does something different: it links two moments together. Every perfect form says this happened before that, and it matters at that point. Once you read perfect forms as relationship markers rather than as extra tenses, the NTS items built on them become mechanical.
The Complete Tense-Aspect Grid
| Simple | Progressive | Perfect | Perfect Progressive | |
|---|---|---|---|---|
| Past | wrote | was writing | had written | had been writing |
| Present | writes | is writing | has written | has been writing |
| Future | will write | will be writing | will have written | will have been writing |
Present Perfect: The Past With a Present Address
Form: has / have + past participle.
Present perfect is used when a past action still has a live connection to now:
- Unfinished time period: I have attempted the GAT twice this year. (the year is not over)
- Life experience, time unspecified: She has visited Skardu. (when is irrelevant)
- Present result of a past act: He has lost his CNIC. (so he cannot enter the hall today)
- Recent news: NTS has uploaded the answer keys.
The Finished-Time Incompatibility
This is the rule NTS tests most often. Present perfect cannot appear with an adverbial that closes off the time period:
- Wrong: I have submitted my form yesterday.
- Right: I submitted my form yesterday. / I have submitted my form.
If the sentence names a finished time — yesterday, last Friday, in 2015, two weeks ago, when I was in Multan — the verb must be past simple. If the time is unfinished or unnamed — today, this week, so far, already, just, ever, never, recently — present perfect is available.
Since Versus For
| Word | Takes | Example |
|---|---|---|
| since | a point in time | since 2021, since March, since I graduated |
| for | a duration | for three years, for six months, for a long time |
She has been preparing since January. / She has been preparing for seven months. Swapping them is a standard distractor.
Past Perfect: Ordering Two Past Events
Form: had + past participle. Past perfect earns its place only when there are two past events and you need to mark which came first.
- By the time the invigilator collected the papers, Bilal had bubbled every answer.
- The centre had closed before we reached it.
With a single past event, past perfect is wrong: Yesterday I had gone to Lahore should be Yesterday I went to Lahore. Candidates who treat had as a more formal did lose marks on exactly this.
When before or after already makes the order explicit, past simple is acceptable in both clauses — the conjunction is doing the sequencing work.
Perfect Progressive: Duration Up To a Point
Perfect progressive combines completion-relevance with ongoing duration, and it is the natural answer whenever the sentence contains a length of time plus an emphasis on continuity:
- He has been studying analytical reasoning for three hours. (and may still be)
- She was exhausted because she had been travelling since dawn.
- By December I will have been teaching at this college for a decade.
Compare I have read the passage (finished, result matters) with I have been reading the passage (duration matters, possibly unfinished).
Sequence of Tenses in Reported Speech
When a reporting verb is in the past (said, told, explained, announced), each verb in the reported clause shifts one step back:
| Direct speech | Reported speech |
|---|---|
| present simple → | past simple |
| present progressive → | past progressive |
| present perfect → | past perfect |
| past simple → | past perfect |
| will → | would |
| can → | could |
| may → | might |
"I am revising geometry," she said. → She said that she was revising geometry.
The permanent-truth exception: statements that remain true are not back-shifted. The teacher said that light travels faster than sound — not travelled. NTS builds items around this exception because most candidates back-shift mechanically.
Pronouns and time words shift too: now becomes then, today becomes that day, tomorrow becomes the next day, here becomes there.
Active and Passive Voice
Form: be + past participle, where be carries the tense of the original active verb. The object of the active sentence becomes the subject of the passive one.
| Active | Passive |
|---|---|
| NTS conducts the test. | The test is conducted by NTS. |
| NTS conducted the test. | The test was conducted by NTS. |
| NTS has conducted the test. | The test has been conducted by NTS. |
| NTS is conducting the test. | The test is being conducted by NTS. |
| NTS will conduct the test. | The test will be conducted by NTS. |
Two forms have no ordinary passive: perfect progressive (has been being conducted is not used) and future progressive. If an option offers one of those, it is a distractor.
The agent phrase with by is dropped whenever the doer is unknown, obvious, or irrelevant — which is why official and scientific writing leans on the passive: Roll number slips are uploaded seven days before the test.
Which sentence is grammatically correct?
Convert to reported speech: The lecturer said, "Water boils at one hundred degrees Celsius."
Choose the correct passive form of "NTS is preparing the answer keys."
Identify the sentence in which past perfect is used correctly.