CONTRAST PRESENT PERFECT vs. PAST SIMPLE
| Present Perfect Tense | Past Simple Tense |
|---|---|
| undefined time | defined time |
| She has had a baby. | She had a baby last month. |
| (no time adverbs or time expressions, we do not know when it happened) | (the time adverb/time expression – i.e. yesterday, on Monday, last and ago – specifies when it happened) |
| defined time within an unfinished period of time | defined time within a finished period of time |
| I have seen the doctor twice this week. | I saw the doctor last week. |
| (with today and this + time expression) | (see above) |
| frequency adverbs (ever, never, etc.) and time adverbs (already, just, yet, lately, etc.) | When ... ? What time ... ? |
| I’ve never met Dr Jones but I’ve already met his assistant. | When/What time did you arrive? |
| (with when e what time the Past Simple is always used) |
Be careful!
You can use the Past Simple even though the time expression is not present when:
there are historical events which clearly took place in the past:
Smallpox was an infectious disease caused by one of two virus variants.
(the World Health Organization certified the global eradication of the disease in 1980)the person who performed the action cannot repeat it because, for example, is dead:
Christian Barnard performed sixty heart transplants.
(the South African cardiac surgeon died in 2001)
BUT Devi Shetty has performed more than 15,000 heart operations. (the Indian cardiac surgeon is still alive and can perform more operations)
- an action has become defined in the mind of the interlocutors. A conversation about a past action often starts with a question and an answer in the Present Perfect, but then it normally goes on with the Past Simple.
Example:
A. What have you done today? – B. I’ve been to the hospital.
A. Why did you go there? – B. I visited a friend of mine who’s just had a baby.
14 Complete with the Present Perfect or the Past Simple.
A. Where .......................................... (be) this morning?
B. I .......................................... (be) to the doctor’s.
A. What .......................................... (tell) you?
B. He .......................................... (give) me some vitamins and .......................................... (check) my weight.
A. .......................................... (you / ever / be) to a nutritionist’s?
B. Yes, I .......................................... .
A. .......................................... (she / put) you on a diet?
B. No, she .......................................... .
A. Is your sister married?
B. Yes, she .......................................... (be) married for ages. About ten years.
She .......................................... (get) married when she was only 18.
Mother: .......................................... (you / do / already) your homework?
Daughter: No, I .......................................... (come / just) home from school.
Mother: You .......................................... (come) home from school two hours ago!
Daughter: Well, but my friend Lucy .......................................... (call) when I .......................................... (arrive) and I .......................................... (finish / just) the phone call.