English Grammar Lab

← B1

Time expressions with the present perfect

You will be able to Use for, since, already and yet accurately with the present perfect.

Explanation

For introduces a duration and since introduces a starting point. Already normally appears in affirmative sentences, while yet is common in questions and negatives.

Examples

Detailed course

Understand the grammar point

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Detailed explanation

This lesson focuses on time expressions with the present perfect. The structure helps learners organise connected speech and writing, and it should always be interpreted as part of a complete message rather than as an isolated formula. Before selecting a form, identify the subject, time reference, clause relationship, and the information that receives emphasis.

Formation is central. Use for plus a period, since plus a starting point, already mainly before the past participle in affirmative clauses, and yet at the end of questions and negatives. Build the sentence in stages: identify the grammatical subject, choose the auxiliary or main verb form, and complete the clause in normal English word order. In negatives and questions, check whether the structure supplies its own auxiliary or requires another one.

The pattern can help users explain reasons and results, report experience and information, and choose between related grammar patterns. These purposes may overlap, so context decides which interpretation is natural. Time expressions, determiners, linking words, and punctuation often provide evidence for the correct choice.

A useful contrast prevents overgeneralisation. Ago normally belongs with the past simple, while for and since can connect a continuing situation to the present. Ask how the nearest alternative would change time, certainty, focus, politeness, or register. A grammatically possible sentence may still communicate the wrong relationship if that contrast is ignored.

The guided examples are complete messages. Notice how the target structure agrees with its subject and how the surrounding vocabulary makes the intended meaning clear. When producing a new example, preserve the relationship between form and meaning while changing the people, place, and lexical details.

A reliable self-check is to paraphrase the sentence in simpler language. If the paraphrase changes the time relationship, degree of certainty, or focus, review the original form. Compare the sentence with the common mistakes and explain why the corrected version is preferable.

In connected speech and writing, the structure also contributes to cohesion. It guides the reader through background information, main events, causes, qualifications, and results. Clause order and connector choice can therefore affect interpretation even when every individual word is correct.

How to form it

Use for plus a period, since plus a starting point, already mainly before the past participle in affirmative clauses, and yet at the end of questions and negatives.

Use the structure to organise connected speech and writing.

Use the structure to explain reasons and results.

Use the structure to report experience and information.

Use the structure to choose between related grammar patterns.

Ago normally belongs with the past simple, while for and since can connect a continuing situation to the present.

Guided examples

I have worked on the community garden for six months.

For introduces a duration, six months, showing how long the action has continued.

Our group has met every Saturday since January.

Since introduces the starting point, January, of the ongoing action.

The volunteers have already planted the first trees.

Already appears in an affirmative sentence, before the past participle planted.

We have not finished the new path yet.

Yet appears at the end of this negative sentence, showing the action is still expected.

Has the council approved the final plan yet?

Yet appears at the end of this question, asking if something expected has happened.

Mina has known the project leader since primary school.

Since introduces the starting point, primary school, of a state that continues now.

Common mistakes

Not: I have worked on the community garden since six months.

Use: I have worked on the community garden for six months.

Six months is a duration, so it needs for, not since.

Not: Our group has met every Saturday for January.

Use: Our group has met every Saturday since January.

January is a starting point, so it needs since, not for.

Not: The volunteers have planted already the first trees.

Use: The volunteers have already planted the first trees.

Already normally goes before the past participle, not after it: have already planted.

Not: We have not finished yet the new path.

Use: We have not finished the new path yet.

Yet normally goes at the end of a negative sentence, after the object.

Before you practise

  • Identify the communicative purpose.
  • Check the subject and required verb or auxiliary.
  • Confirm the time reference and clause order.
  • Compare the sentence with the nearest alternative.
  • Read the complete sentence and verify the meaning.

Reading text

Six Months in the Community Garden

About 267 words

Samira, the volunteers, and local children gathered at a community garden behind the clinic to review progress before an open morning. The main difficulty was clear: the garden looks lively but a few jobs remain unfinished. They spread herbs, tools, and a half-built shed across the table and agreed to work through the facts one by one. The garden has existed since April. That first detail changed the mood in the room because it gave the group something concrete to discuss. We have worked here for six months. After that, the group compared names, times, and places instead of guessing. The volunteers have already planted herbs. A short disagreement followed, but it helped them notice a missing detail. They have not built the tool shed yet. When the final note was added, the plan felt realistic and easy to explain. Before they left a community garden behind the clinic, the result was clear: the volunteers agree on the next weekend tasks. Samira, the volunteers, and local children return to herbs, tools, and a half-built shed because each item helps with the task. The notes show why the garden looks lively but a few jobs remain unfinished. The group checks the time, the place, and the next decision before moving on. No one rushes, because a small error would change the outcome. The work stays connected to a community garden behind the clinic, where the problem first became visible. By the end, the result is clear: the volunteers agree on the next weekend tasks. Later, the written record helps the group explain the decision without adding new claims.

Reading comprehension

  1. Who is involved in the reading?

    Show answer

    Samira, the volunteers, and local children

  2. Where does the reading take place?

    Show answer

    a community garden behind the clinic

  3. What task are the people trying to complete?

    Show answer

    review progress before an open morning

  4. What problem makes the task less simple?

    Show answer

    the garden looks lively but a few jobs remain unfinished

  5. How does the reading end?

    Show answer

    the volunteers agree on the next weekend tasks

Grammar in the text

  1. The garden has existed since April.

    Since introduces April, the starting point of a situation that continues now.

  2. We have worked here for six months.

    For introduces six months, a duration, not a starting point.

  3. The volunteers have already planted herbs.

    Already appears before the past participle in this affirmative sentence.

  4. They have not built the tool shed yet.

    Yet appears at the end of this negative sentence, showing the action has not happened.

Key point

Use this pattern when the meaning needs it in the reading: have/has + past participle + time expression. In short, for, since, already, and yet add time meaning to the present perfect. Example: "The garden has existed since April."

Practice

  1. Complete the sentence from the same situation: "The garden ____ existed since April."

    Show answer

    The garden has existed since April.

  2. Complete the sentence from the same situation: "We have ____ here for six months."

    Show answer

    We have worked here for six months.

  3. Complete the sentence from the same situation: "The volunteers ____ already planted herbs."

    Show answer

    The volunteers have already planted herbs.

  4. Complete the sentence from the same situation: "They have ____ built the tool shed yet."

    Show answer

    They have not built the tool shed yet.

Listening practice

Watch a TEDx talk

“TED's secret to great public speaking” — Chris Anderson (TED). Listen for clear, natural English and pick up new vocabulary while you review this grammar point.

Check your understanding

According to Chris Anderson, what is the one underlying thing that all great talks have in common?

Check your understanding

What does Anderson warn speakers against doing on the TED stage?

Practice

Choose the correct answer. We have known each other ___ ten years.

Practice

Choose the correct answer. He has been here ___ Monday.

Practice

Choose the correct answer. I haven't completed the exercise ___.

Written practice

Produce the answer yourself. Capitalisation and final punctuation do not affect validation, but the grammar and word order must be correct.

Short answer

Written practice

Complete the sentence with for or since.

She has worked here ___ May.