Present Perfect vs Past Simple: The One Rule That Decides It

The one-line answer

Ask one question: is the time period finished? If it is finished, use the past simple. If it still includes now, or if the sentence names no time at all, use the present perfect. The verb itself does not decide this — the time frame around it does.

• We signed the contract **on Monday**. — Monday is over, so the past simple is the only option.
• We have signed the contract. — No time is given. The point is that the contract is signed now.
• We have signed three contracts **this month**. — This month is still running, so the count can still change.

A useful reversal: the present perfect is about the present. It uses a past participle, but what it reports is the situation as it stands now. The past simple is about a moment that has closed.

The time-expression test

Most exam sentences hand you the answer in a time expression. Find it first, and the tense follows.

“This morning” belongs to both rows, and which one depends on when you speak. At 10 a.m. the morning still includes now, so “I have read the report this morning” works. At 4 p.m. the morning has closed, so it becomes “I read the report this morning.”

Why “I have seen him yesterday” is wrong

This is the single most common error with these two tenses, and the reason is mechanical rather than stylistic. The present perfect places an event in a period that reaches the present. The word yesterday names a period that stopped at midnight. The sentence therefore asks one event to sit inside both an open and a closed time frame, and the two cannot be true together.

The repair is to pick which meaning you want. “I saw him yesterday” reports when. “I have seen him” reports that the meeting has happened and may matter now. You cannot have both in one clause, though you can have both in one sentence: “I have spoken to him, and we met yesterday.”

Formal reference: British Council on the present perfect and on the past simple. For how these two sit among the other ten, see the 12 English tenses, with a chart and formulas.

Since and for: the pair people swap

Since marks a starting point. For marks a length. They answer different questions, so they are not interchangeable even though both often appear with the present perfect.

• since + a point in time: since 2019, since March, since the merger, since I joined.
• for + a length of time: for six months, for three years, for a long time.
• Since almost always takes the present perfect, because it measures up to now.
• For does not. “I worked there for five years” is correct and means the five years are over.

That last line is where most of the real confusion lives. For is tense-neutral; since is not. If an exam option offers for with a past simple, do not reject it on sight — check whether the period has closed.

Already, yet and just

These three words report how an event stands in relation to now, which is exactly the present perfect's job.

• already — sooner than expected: “The shipment has already arrived.”
• yet — expected but still missing, used in questions and negatives: “We have not received the invoice yet.”
• just — a very short time ago: “She has just left the office.”

Yet sits at the end of the clause. Already and just sit between have and the past participle. Getting the position wrong is a separate mistake from getting the tense wrong, and exam options test both.

American English breaks one of these rules

In American English the past simple is routinely used with already, yet and just: “Did you eat yet?” and “I just ate” are both normal. British English keeps the present perfect there. Both varieties are standard in their own setting, so this is a genuine difference rather than an error.

For an exam, that difference has a simple practical consequence. The present perfect is acceptable in both varieties, the past simple only in one, so when both appear as options and nothing else separates them, the present perfect is the safer answer.

Six sentences to work through

Decide before reading the reason. The time expression does the work in five of the six.

1. 1The shipment ___ (arrive) last Tuesday. → **arrived**. Last Tuesday is closed.
2. 2We ___ (not receive) the invoice yet. → **have not received**. Yet reports a present gap.
3. 3She ___ (work) in Bangkok from 2015 to 2019. → **worked**. The dates close the period.
4. 4I ___ (send) the report, so you should have it now. → **have sent**. No time named; the result is present.
5. 5___ you ___ (speak) to the supplier this morning? Asked at 4 p.m. → **Did you speak**. The morning is over.
6. 6The company ___ (open) three branches since January. → **has opened**. Since runs up to now, and the number can still rise.

Item 4 is the one with no time expression. When nothing names a time, ask what the sentence is for: reporting a present state points to the present perfect, narrating an event points to the past simple.

Where this shows up on the TOEIC

Sentence-completion items rarely ask you to define a tense. They give four forms of one verb and bury a time expression somewhere in the stem, so the fastest route is to find that expression before reading the options at all.

That habit generalises: the same scan finds the trigger words behind other verb questions. See verb forms and the words that decide them, the wider routine in TOEIC Part 5 tips, the matching decision set for the future in future tenses in English, and how the past simple sits among the other past forms in past tenses in English.