The present perfect and the past simple divide the timeline between open and closed periods. Today is still open while the clock is running, so "I have answered twenty emails today" is normal. Yesterday is closed, so "I answered twenty emails yesterday" is the natural sentence.
The same words can move between the two tenses when the period closes. This morning takes the present perfect at 10 a.m. and the past simple at 9 p.m. The tense follows the clock, not the calendar alone.
This page explains the open and closed periods, the special case of this morning and this afternoon, and the phrases so far, up to now and yet. The 20-question drill checks the boundary with a short rule under every answer.
The rule
Unfinished time and finished time
- Time words divide into open and closed periods.
- Today, this week, this month and this year are still open.
- Yesterday, last week, last year and in 2019 are closed.
- An open period takes the present perfect; a closed period takes the past simple.
Today and this week in use
- "I have answered ten emails today" means the day is not over.
- "I answered ten emails yesterday" means the day is finished.
- "She has visited three countries this year" is true so far.
- "She visited three countries last year" is a closed total.
This morning, this afternoon and this evening
- The tense depends on whether the period is over.
- At 10 a.m. you say: "I have drunk two coffees this morning."
- At 9 p.m. you say: "I drank two coffees this morning."
- The clock decides the tense, not the words alone.
So far, up to now and recently
- So far and up to now open the period: "We have sold 40 tickets so far."
- Recently and lately can take either tense, depending on the focus.
- Already, yet and just fit the recent open period: "I have just finished."
- A finished time expression overrides the present perfect: "I finished just now."
Questions and negatives
- Questions about an open period take the present perfect: "Have you seen Sam today?"
- Negative answers often switch to the past simple when a finished detail appears.
- "I have not seen him today" keeps the open period.
- "I did not see him yesterday" names a closed period.
Examples
- I have answered twenty emails today.The day is still open.
- She has visited three countries this year.The year is still running.
- We have sold forty tickets so far.So far keeps the period open.
- Have you seen Sam today?A question about an open period takes the present perfect.
- I have not had lunch yet.Yet looks forward inside the open period.
- He has just finished the report.Just places the action in the recent open period.
- I drank two coffees this morning, and now it is evening.The morning is over, so the past simple takes over.
- She visited Rome last year.Last year is a closed period.
- We met yesterday morning.Yesterday is closed.
- They have lived here for five years.The period continues up to now.
Common mistakes
- Wrong: I have answered ten emails yesterday. Right: I answered ten emails yesterday.
- Yesterday is a finished period, so the past simple is required.
- Wrong: I answered ten emails today. Right: I have answered ten emails today.
- Today is still open, so the present perfect is the natural choice.
- Wrong: We have sold 40 tickets last week. Right: We sold 40 tickets last week.
- Last week is closed and cannot take the present perfect.
- Wrong: She has visited Paris in 2019. Right: She visited Paris in 2019.
- A year in the past is a finished time expression.
- Wrong: I have drunk two coffees this morning, and now it is 9 p.m. Right: I drank two coffees this morning, and now it is 9 p.m.
- The morning is over, so the past simple reports the total.
Practice drill
Answer all 20 questions. Each answer is marked at once, and the rule is explained under the question.
I ___ twenty emails today.
Show answer and explanation
Answer: A. have answered Today is unfinished time, so the present perfect have answered is correct.
She ___ three countries this year.
Show answer and explanation
Answer: B. has visited This year is still open, so the present perfect has visited fits.
We ___ forty tickets so far.
Show answer and explanation
Answer: C. have sold So far opens the period up to now, so the present perfect is correct.
___ you seen Sam today?
Show answer and explanation
Answer: D. Have A question about today takes the present perfect auxiliary have.
I ___ not had lunch yet.
Show answer and explanation
Answer: A. have Yet belongs to the open period, so the present perfect have not had is correct.
He ___ just finished the report.
Show answer and explanation
Answer: B. has Just works with the present perfect has finished.
I ___ two coffees this morning, and it is only 10 a.m.
Show answer and explanation
Answer: C. have drunk The morning is still open at 10 a.m., so the present perfect is correct.
I ___ two coffees this morning, and now it is 9 p.m.
Show answer and explanation
Answer: D. drank The morning is over, so the finished time takes the past simple drank.
She ___ Rome last year.
Show answer and explanation
Answer: A. visited Last year is a finished period, so the past simple visited is correct.
We ___ yesterday morning.
Show answer and explanation
Answer: B. met Yesterday is finished time, so the past simple met is correct.
They ___ in this city for five years.
Show answer and explanation
Answer: C. have lived For five years continues to now, so the present perfect have lived fits.
I ___ him yesterday.
Show answer and explanation
Answer: D. did not see Yesterday is a closed period, so the past simple did not see is correct.
I ___ him today.
Show answer and explanation
Answer: A. have not seen Today is still open, so the present perfect have not seen is correct.
How many books ___ this month?
Show answer and explanation
Answer: B. have you read This month is unfinished time, so the present perfect is correct.
How many books ___ last month?
Show answer and explanation
Answer: C. did you read Last month is finished time, so the past simple did you read is correct.
She ___ a lot this year.
Show answer and explanation
Answer: D. has achieved This year is still running, so the present perfect has achieved fits.
We ___ the project last week.
Show answer and explanation
Answer: A. finished Last week is a closed period, so the past simple finished is correct.
___ you finished your homework yet?
Show answer and explanation
Answer: B. Have Yet belongs to the open period, so the present perfect auxiliary have is correct.
The shop ___ 30 orders so far today.
Show answer and explanation
Answer: C. has received So far today keeps the period open, so the present perfect has received fits.
The shop ___ 30 orders yesterday.
Show answer and explanation
Answer: D. received Yesterday is finished time, so the past simple received is correct.
Drill complete
You answered every question.
Next topic: Past perfect continuous: had been doingTake the level test
Questions learners ask
Why does "this morning" take two different tenses?
Because the period moves. At 10 a.m. the morning is still open, so the present perfect reports what has happened so far: "I have drunk two coffees this morning." At 9 p.m. the morning is a closed block, so the past simple reports the total: "I drank two coffees this morning."
Does "recently" take the present perfect or the past simple?
Both are possible, with a difference in focus. The present perfect connects the recent event to now: "I have recently changed jobs." The past simple places it at a finished point: "I recently changed jobs." British English prefers the present perfect more often than American English does.
Can I use "just" with the past simple?
In British English, just usually takes the present perfect: "He has just left." In American English, just now and the past simple are common: "He just left." Both are understood, but keep just with the present perfect in formal writing, and avoid "he has just now left".
More grammar topics
Past perfect continuous: had been doing
Had been plus -ing describes an activity that was in progress before another past moment. It stresses the duration, not the finished result.
Too much vs too many: countable and uncountable
Too much takes uncountable nouns such as water and time. Too many takes countable plural nouns such as books and people. Enough goes after an adjective and before a noun.
Each vs every: one by one or all together
Each sees the members of a group one by one. Every sees the whole group together. Both take a singular noun and a singular verb.
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