Mastery check pending

GS3.03CEFR B1Tense, aspect and time reference

Present perfect systems

The present perfect connects a past situation with the present through result, experience, duration or an unfinished time period.

01 · Concept foundation

Understand the terms before applying the rule

Each term below names a different grammatical object. Open examples and compare their function rather than memorising a Vietnamese translation alone.

T01

present perfect/ˌprezənt ˈpɜːfekt/

hiện tại hoàn thành

The have/has + past participle construction linking a prior situation to the present reference point.

Researchers have monitored the site since 2021.

Các nhà nghiên cứu đã giám sát địa điểm từ năm 2021.

T02

current relevance/ˈkʌrənt ˈreləvəns/

tính liên quan hiện tại

A present consequence or significance of an earlier event.

The storm has damaged the gauge, so no data are available.

Bão đã làm hỏng máy đo nên hiện không có dữ liệu.

T03

unfinished time/ʌnˈfɪnɪʃt taɪm/

khoảng thời gian chưa kết thúc

A time period that includes the present and therefore permits present-perfect reference.

this year, so far, since 2021

năm nay, cho đến nay, từ năm 2021

Complete lesson scope

Do not stop at one formula

4 coverage areas

Past experience with present relevance

Unfinished time periods and repeated events

Present perfect simple versus continuous

For, since, already, yet, just, ever and never

Decision boundary: Do not combine the present perfect with a finished past-time expression such as yesterday or in 2019.

02 · Controlling rule

The present perfect places the event before now but evaluates it from the present reference point. Use have/has + V3 for current results, experience without a finished time, change up to now and events in an unfinished period. The present perfect progressive adds been + V-ing and foregrounds duration, repetition or process. Use past simple when the speaker locates the event in a finished past frame such as yesterday, last year or a completed chart period.

Structural formula

perfect: S + have/has (not) + V3 | Have/Has + S + V3? || perfect progressive: S + have/has (not) been + V-ing | Have/Has + S + been + V-ing?

GS3 · Time-reference laboratory

Present perfect as a bridge from earlier time to now

Distinguish present perfect simple, present perfect progressive and past simple by identifying whether the time frame is open, whether the result matters now, and whether the speaker foregrounds completion, count or duration.

Reference modules4Meaning → form → discourse

Scientific concept model

The perfect relates an earlier event time to a later reference time; in the present perfect, the reference time is now.

The present perfect does not simply mean 'past'. It asks the reader to evaluate an earlier event from the present reference point. The past simple instead places the event inside a finished past frame and reports it there.

E · R · S relationPresent perfect: E < R = S, with a current connection | Past simple: E = R < S, closed past frame

E = event time · R = reference time · S = speaking/writing time

Module 01

Current relevance and open time

Present perfect is licensed when the speaker keeps the reference frame connected to now: a current result, life experience, repeated event in an unfinished period or a state continuing to the present.

Form systemhave/has + V3 → earlier event evaluated at R = now

Use present perfect for a current result when the exact past time is not the focus: The sensor has failed, so no data are available now.

Use it for experience at an unspecified time before now: Have you ever worked offshore?

Use it for repeated events in an unfinished period: We have sampled four times this month.

Use it with states beginning earlier and continuing now: The station has operated since 2018.

Analysed example 1

The project has produced three peer-reviewed articles so far.

So far keeps the evaluation period open at the present; the number three foregrounds completed results.

multiple E before R = now; period remains open

Analysed example 2

Researchers have known about the interaction for decades.

Know is stative, so present perfect simple expresses a state extending to now.

state E begins earlier and includes R = now

Complete morphology

Affirmative, negative and question forms

Present perfect simple

+ Affirmative: S + have/has + V3
− Negative: S + have/has not + V3
? Question: Have/Has + S + V3?

•Use the past participle, not the past form: has gone, has written, has taken.
•Have contracts to 've and has to 's in informal speech/writing where ambiguity is acceptable.

Present perfect continuous

+ Affirmative: S + have/has been + V-ing
− Negative: S + have/has not been + V-ing
? Question: Have/Has + S + been + V-ing?

•Been is required between have/has and V-ing.
•The form commonly foregrounds duration or recent process, not necessarily completion.

Viewpoint contrasts

Similar situation, different grammatical choice

Completed result versus activity in progress

completed result

I have read the report.

The report is now read and available for discussion.

ongoing/recent process

I have been reading the report.

The reading activity is foregrounded; completion is not guaranteed.

Decision rule: Use simple for endpoint/result; continuous for duration/process or visible recent effort.

Net change versus developing trend

measured result

Mean sea level has increased by 12 centimetres.

The sentence foregrounds the accumulated amount of change.

continuing trend

Mean sea level has been increasing for decades.

The sentence foregrounds duration and trend continuity.

Decision rule: A by-amount result favours simple; a for/since duration and ongoing trend favour continuous.

Experience versus dated event

life experience

I have visited the Delta Works.

No finished date is selected; the experience is relevant now.

dated past event

I visited the Delta Works in 2023.

In 2023 closes the time frame and selects past simple.

Decision rule: Experience without a finished date uses present perfect; details in a closed past frame use past simple.

What speakers and writers actually prefer

Conversation and recent news

Present perfect introduces experience/current result; past simple supplies when, where and what happened next.

Conversation moves from present relevance to specific narrative detail.

Academic literature review

Present perfect for cumulative research up to now; past simple for a specific dated study; present simple for an accepted claim.

The tense signals the writer's relationship to evidence and current knowledge.

IELTS Academic data description

Use present perfect only when the chart period extends to the present or the change is explicitly current; otherwise use the tense required by the dated period.

The data time frame, not a memorised template, controls tense.

Time-expression diagnostics

Interpret the whole time frame; this morning may be open at 9 a.m. but closed in the evening.

Expression	Typical frame	Typical form
yesterday / in 2019 / last month	closed past	past simple
so far / up to now	open to present	present perfect
since + starting point	from start to reference time	present perfect simple/continuous
for + duration	duration up to reference time	perfect form if still connected
already / yet / just	current result/recent completion	often present perfect

Simple versus continuous focus

Some verbs allow both; the communicative focus decides.

Focus	Simple	Continuous
completion	foregrounded	not necessarily asserted
quantity/count	natural	usually secondary
duration/process	possible with states	strongly foregrounded
temporary recent activity	possible if result matters	often preferred

Error laboratory

High-risk tense and aspect errors

The survey has finished yesterday.

The survey finished yesterday.

Yesterday closes the reference frame, so past simple is required.

The team has went offshore.

The team has gone offshore.

Present perfect requires the past participle gone, not the past form went.

The station has operated since five years.

The station has operated for five years.

For introduces duration; since introduces a starting point.

They have monitoring the inlet since dawn.

They have been monitoring the inlet since dawn.

Present perfect continuous requires have/has + been + V-ing.

Real-use and IELTS transfer

Apply the time system in a complete message

Write a three-sentence mini literature review: sentence 1 summarises cumulative research with present perfect; sentence 2 identifies one dated study with past simple; sentence 3 states the current interpretation with present simple.

✓The present-perfect sentence has an open/current research frame.
✓The past-simple sentence includes a finished date or clearly closed event.
✓Past participles and have/has agreement are correct.
✓The tense shifts are explained by reference-time changes, not random variation.

Global tense–aspect matrix

Twelve pedagogical forms organised by time and viewpoint

English directly inflects verbs mainly for present and past. The familiar ‘twelve tenses’ are a useful teaching matrix that combines time reference with four aspectual viewpoints; future reference is built with auxiliaries, present forms and context. Therefore, choose a form from meaning and discourse, not from a time word alone.

Eevent time

Rreference time

Sspeech/writing time

presentsimple viewpoint

Present simple

R = S; situation viewed as a state, whole or repeated pattern

facts, stable states, routines, instructions, commentary and fixed schedules

Real use: Very frequent in conversation; central in definitions, methods and figure descriptions.

+ Affirmative: S + V(s/es)
− Negative: S + do/does not + V
? Question: Do/Does + S + V?

The station records tides every ten minutes.

presentinside an unfolding event

Present progressive

E overlaps R = S; speaker views the event from inside

activity around now, temporary situations, developing change and arranged future events

Real use: Very common in conversation; used selectively in reports when ongoing change is the focus.

+ Affirmative: S + am/is/are + V-ing
− Negative: S + am/is/are not + V-ing
? Question: Am/Is/Are + S + V-ing?

The shoreline is retreating rapidly this decade.

presentanterior event linked to a reference point

Present perfect

E precedes R = S; result, experience or open period remains relevant

past events with a current result, life experience, change up to now and unfinished time periods

Real use: Common in conversation for news and experience; frequent in introductions and literature reviews.

+ Affirmative: S + have/has + V3
− Negative: S + have/has not + V3
? Question: Have/Has + S + V3?

Researchers have identified three dominant processes.

presentanterior duration or process

Present perfect progressive

E starts before R = S and extends to/near R; duration or process is foregrounded

ongoing or recently stopped activity with emphasis on duration, repetition or visible consequences

Real use: Natural in conversation; useful in process reports, but less suitable for stative meanings.

+ Affirmative: S + have/has been + V-ing
− Negative: S + have/has not been + V-ing
? Question: Have/Has + S + been + V-ing?

The team has been monitoring salinity since March.

pastsimple viewpoint

Past simple

E = R < S; event is located in a finished past frame and viewed as a whole

completed events, past states, ordered narrative events and finished data periods

Real use: The default tense for recounting in speech and for reporting completed methods/results.

+ Affirmative: S + V2/V-ed
− Negative: S + did not + V
? Question: Did + S + V?

The sensor failed during the storm.

pastinside an unfolding event

Past progressive

E contains R < S; event is viewed from inside at a past reference point

background activity, an event in progress at a past time, parallel processes and temporary past situations

Real use: Frequent in spoken narratives; valuable in incident reports for background conditions.

+ Affirmative: S + was/were + V-ing
− Negative: S + was/were not + V-ing
? Question: Was/Were + S + V-ing?

The team was collecting samples when the pump stopped.

pastanterior event linked to a reference point

Past perfect

E < R < S; one event is explicitly anterior to a past reference point

earlier past events, causes already completed before a past result and narrative backtracking

Real use: Used when chronology would otherwise be unclear; common in formal incident and research narratives.

+ Affirmative: S + had + V3
− Negative: S + had not + V3
? Question: Had + S + V3?

The battery had failed before the warning appeared.

pastanterior duration or process

Past perfect progressive

E extends toward R < S; earlier duration/process explains a past state or result

duration or repeated activity continuing up to a past reference point, often with a past consequence

Real use: Less frequent than past simple, but precise in narratives and technical root-cause explanations.

+ Affirmative: S + had been + V-ing
− Negative: S + had not been + V-ing
? Question: Had + S + been + V-ing?

The pump had been vibrating for hours before it failed.

futuresimple viewpoint

Future with will

R > S; future reference is expressed through modal will rather than a dedicated tense ending

neutral predictions, spontaneous decisions, promises, offers and formal projections

Real use: Very common in speech for decisions; frequent in academic forecasting with calibrated probability language.

+ Affirmative: S + will + V
− Negative: S + will not + V
? Question: Will + S + V?

The revised barrier will reduce overtopping risk.

futureinside an unfolding event

Future progressive

E contains future R; event is expected to be in progress at that point

activity in progress at a future time, expected routine and polite questions about plans

Real use: Useful in planning meetings and operational writing; often sounds less imposing in questions.

+ Affirmative: S + will be + V-ing
− Negative: S + will not be + V-ing
? Question: Will + S + be + V-ing?

We will be surveying the inlet at 09:00 tomorrow.

futureanterior event linked to a reference point

Future perfect

E precedes future R; completion is evaluated from that later point

work expected to be complete before a future deadline or reference point

Real use: Especially useful in project plans, milestones, forecasts and formal progress statements.

+ Affirmative: S + will have + V3
− Negative: S + will not have + V3
? Question: Will + S + have + V3?

By Friday, the team will have completed the calibration.

futureanterior duration or process

Future perfect progressive

E extends to future R; duration is measured from that future viewpoint

duration of an activity continuing up to a future reference point

Real use: Relatively rare in casual speech; precise for duration in planning, staffing and longitudinal reporting.

+ Affirmative: S + will have been + V-ing
− Negative: S + will not have been + V-ing
? Question: Will + S + have been + V-ing?

By July, they will have been monitoring the site for two years.

03 · Worked examples

Observe form, function and meaning together

EX01

The revised model has reduced the mean error.

Mô hình sửa đổi đã làm giảm sai số trung bình và kết quả này còn liên quan hiện tại.

EX02

Researchers have studied this inlet for more than thirty years.

Các nhà nghiên cứu đã nghiên cứu cửa biển này hơn ba mươi năm.

EX03

The team has been collecting hourly samples since March.

Nhóm đã liên tục lấy mẫu theo giờ từ tháng Ba đến nay.

EX04

The survey ended in 2024, but its dataset has become a regional reference.

Khảo sát kết thúc năm 2024, nhưng bộ dữ liệu của nó đã trở thành tài liệu tham chiếu khu vực.

04 · High-risk contrast

Explain why one form fails, not only which answer is correct

Incorrect

The team has completed the survey last Friday.

Repaired

The team completed the survey last Friday.

Last Friday creates a finished past reference frame. The present perfect cannot normally be anchored to that completed time in standard British-oriented academic usage.

05 · Mastery check

Apply the rule before marking the lesson complete

Progress0/4 + 0/1

Q01

Which sentence is grammatically acceptable in the target system?

Q02

Which description best defines “present perfect”?

Q03

Which example is one of the verified target patterns in this lesson?

Q04

Which structural formula belongs to this lesson?

Q05 · Production taskContrast one completed past-time sentence with one present-perfect sentence whose time period is still open.Do not combine the present perfect with a finished past-time expression such as yesterday or in 2020.

Complete all four checks, then submit a sentence for target-form feedback.

06 · IELTS Academic

Transfer grammar into a real communicative task

Use the present perfect in Speaking for experience and developments up to now. In academic introductions and literature reviews, it can summarise research accumulated to the present; switch to past simple for a specific finished study, method or data period. The progressive form is useful for ongoing trends but should not be added merely to sound advanced.

Separate current relevance from finished past location.

Use valid past participles after have/has.

Distinguish result/count from duration/process.

Control since, for, already, yet and finished-time expressions by meaning.