Verb Tenses

All verbs have tenses. The tense is a quality of a verb that indicates when something happened. There are three main tenses, and each of these have four aspects. The three tenses are (1) past, (2) present, and (3) future. The four aspects are (1) simple, (2) perfect, (3) continuous, and (4) perfect continuous.

List of Verb Tenses and How They Function

Different tenses are used to describe when something happened (in the past), happens (now or regularly), or will happen (in the future).

Verb Tense Conjugated Verb When is it used? Example Sentences (using the verb “run”)
Present Simple

run

When making statements that are true regardless of the passage of time

He runs at the park frequently.

Present Continuous

is/are/am running

When describing something that is currently happening

He is running at the park now.

Present Perfect

has/have run

When describing something that began in the past but is likely to go on or to emphasize the effect of a past occurrence on a present situation

He has run every day this week and now looks healthier.

Present Perfect Continuous

has/have been running

When describing something that began in the past but is going on in the present; emphasizes the effect of a past occurrence on a present situation

He has been running for the past hour, and now he must get ready for work.

Past Simple

ran

When describing something that has previously happened

He ran every day for the whole of April.

Past Continuous

was/were running

When emphasizing the ongoing nature of a past occurrence, especially as it relates to another one

He was running at the park when he sprained his ankle.

Past Perfect

had run

When describing a past event that occurred before another past event

He had run daily before he sprained his ankle.

Past Perfect Continuous

had been running

When describing something that began in the past but is continuing into the present or ended very recently

He had been running at the park for two hours, and he had to get ready for work.

Future Simple

will run

When describing something that will happen in the future

He will run every day next month to prepare for the marathon.

Future Continuous

will be running

When describing future events that will likely go on for awhile

He will be running every day to train for the marathon.

Future Perfect

will have run

When describing something that will be completed between the present moment and some specific future moment

He will have run a marathon by the end of next month.

Future Perfect Continuous

will have been running

When describing events that will continue up until a specific future moment; emphasizes the expect duration of the event

He will have been running daily for one month by the time of the marathon.

Present Simple, Past Simple, Future Simple Tenses

The first aspect is “simple.” Present simple is used either to describe an event that is occurring now or that occurs regularly; past simple is used to describe an event that occurred previously; and future simple is used to describe an event that has not yet occurred.

When to use the present simple tense

The most common use of the present simple tense is to describe an event that is happening now. However, present simple is also used for facts that are not affected by the passage of time or for events that regularly occur.

With facts and explanations

Facts, theories, and scientific explanations are not dependent on the passage of time. As such, all statements pertaining to them are written in present tense.

Example
The mass of a closed system remains constant over time.
Example
The results demonstrate that the proposed model can effectively increase the efficiency of data collection.

Describing the content of a text

In many style formatting guides, present tense must be used to describe the content of a text or course. This is because, as with facts and explanations, the content of a text is not affected by the passage of time.

Example
Tolstoy’s Anna Karenina begins with the line, “Happy families are all alike; every unhappy family is unhappy in its own way.”
Example
In their 2015 paper, Mishra et al. state that a wide network of health facilities, community workers, and volunteers is characteristic of Nepal’s health system.

When to use the past simple tense

The past simple tense is used to describe an event that began and ended in the past. This tense is often used when presenting the steps of a study, explaining a historical event, or reporting the news.

Reporting the steps in your research

Past simple tense is often used to describe the methodology and results of a study. This is because the study was (most likely) conducted in the past, and the results were also obtained in the past. Note that the Methods section often employs the passive voice of the simple past tense (as in the examples below).

Example
The compound was synthesized from graphite following the proposed method.
Example
A quantitative thermogravimetric analysis was performed.

Referring to events in the past

The most obvious use of past simple is to describe events that happened in the past. Such an event could be a news or historical event, but it could also be a shopping trip that happened yesterday.

Example
World War II officially ended on September 2, 1945..
Example
I visited my grandmother in Montauk last weekend.

When to use the future simple tense

The future simple tense is used for hypotheses, predictions, or events that will (or will likely) happen in the future. Note that some types of adverbs can be placed between “will” and the main verb, as in the second example below.

Example
We hypothesize that the fabricated composite will exhibit good thermal conductivity.
Example
The proposed approach will likely facilitate the development of thermally conductive materials.
Example
I will visit my cousins in Seattle next month.

Using other verbs instead of future tense

Future simple tense verbs typically imply a high level of certainty. As such, the use of other more “cautious” verbs such as expect, suppose, and assume are often more appropriate in academic writing. Using modal verbs such as may, might, and could also convey possibility without implying certainty.

Example
The proposed approach may facilitate the development of thermally conductive materials.
Example
I might visit my cousins in Seattle next month.

Present Perfect, Past Perfect, Future Perfect Tenses

The second aspect is “perfect.” Perfect tenses are used to indicate an event or action that has been, is, or will be completed (or “perfected”).

When to use the present perfect tense

Present perfect is most frequently used to describe something that began in the past but is likely to go on or to emphasize the effect of a past occurrence on a present situation. However, it can also be used to describe events that happened at an indefinite point in the past.

Describing events in the past at an unspecified time

Present perfect tense can indicate that an event occurred at some previous unspecified time.

Example
Lana has made breakfast for her housemates.
Example
I have met Keanu Reeves once before.

Referring to previous research

Present perfect tense stresses that an action has been completed. As such, it is often used when referring to previous research where the exact study is not specified.

Example
Previous studies have confirmed that this composite material exhibits good thermal conductivity.
Example
We have previously developed a novel platform for large-scale data collection.

Emphasizing the present importance of previous work

Present perfect tense also emphasizes the effect of past events on the present; it is often used to stress the current importance of previous work.

Example
As recent research [1],[5],[24],[26] has demonstrated, the third composite has high fragility, which makes practical application infeasible despite the composite’s high thermal conductivity.

When to use the past perfect tense

Past perfect tense is used to describe a past event that occurred before another past event. It is not often used in academic writing, but it is commonly used in other kinds of writing to order narrative events.

Example
Tommy was surprised to see that Lana had painted her room bright yellow.
Example
I thought, if I had caused the cloud, it was my duty to make an effort to dispel it.

When to use the future perfect tense

Future perfect tense is used to describe something that will be completed between the present moment and some specific future moment. As with past perfect tense, this is not commonly used in academic writing but is used to order narrative events.

Example
Lana will have finished painting her room by tomorrow.
Example
By the end of the week, I will have left for Australia.

Present Continuous, Past Continuous, Future Continuous Tenses

The third aspect is “continuous.” Continuous tenses are used to indicate the ongoing nature of an event.

When to use the present continuous tense

Present continuous tense is used to describe an event that is currently ongoing. This verb tense is not often used in academic writing, but it is common in everyday and other kinds of writing. However, present continuous can also be used to describe the future possibility of an event or the intention to do something in the future. This is useful when discussing future research or the possible outcomes of a study.

Discussing current or ongoing actions or events

Describing continuing actions or events is the most common use of present continuous tense.

Example
Lana is painting her room a bright sunflower yellow.

Discussing future events or research

In academic writing, present continuous is often used to discuss expected outcomes and future research. This is because present continuous can be also used to describe intention.

Example
We are expecting future studies to help further elucidate the mechanics behind this result.
Example
We are planning to further investigate the mechanics behind this result.

When to use the past continuous tense

Past continuous tense is used to emphasize the ongoing nature of a past event, especially as it relates to another event or action in the past.

Example
Lara was painting her room until her brother interrupted.
Example
The company was still recovering from the recession when its CFO died unexpectedly.

When to use the future continuous tense

Future continuous is used to describe events that are likely to go on for some time.

Example
Lana will be painting her room yellow this upcoming weekend.
Example
I will be studying for my exam later.

Using the perfect continuous tense (past, present, future)

Past and present perfect continuous are used to describe events that began in the past but are currently ongoing, as well as to emphasize the effect of the past event or action on the present. Future continuous indicates events that will continue up to a specific moment in the future and emphasizes the expected duration of the event. The following three examples correspond to past perfect continuous, present perfect continuous, and future perfect continuous, in order.

Past Perfect Continuous
He had been learning Japanese for six months when he got the opportunity to visit Japan.
Present Perfect Continuous
He has been learning Japanese for almost three years.
Future Perfect Continuous
Next month, he will have been learning Japanese for three years.