Present perfect with a specific time in the past

by Jakub Marian

Tip: See my list of the Most Common Mistakes in English. It will teach you how to avoid mis­takes with com­mas, pre­pos­i­tions, ir­reg­u­lar verbs, and much more.

The present perfect expresses the idea of “an action that was finished at some unspecified point in the past”. Saying “I have done it yesterday” is basically the same as saying “I finished doing it yesterday at some unspecified point in the past”. It doesn’t really work, does it; it’s either “at some point” or “yesterday”, not both. If you want to include the time when the action took place, you must use the simple past tense (the “-ed” form), e.g.

correct I did it yesterday.
wrong I have done it yesterday.
correct I visited my grandmother last weekend.
wrong I have visited my grandmother last weekend.

However, the simple past is ambiguous. “I did it yesterday” can be used to express that you finished it yesterday as well as that you left the work unfinished and will continue doing it later, as in “I did it yesterday, and I am also going to do it tomorrow”. If you want to express that the action is already completed, you can use verbs like “finish” or “complete” in the simple past:

correct I finished my homework yesterday.
wrong I have finished my homework yesterday.

A strong indicator that you shouldn’t use the present perfect is the presence of “when” in the sentence, since “when” always refers to a specific point in time:

correct When did you write the book?
correct When did you finish writing the book?
probably wrong When have you written the book? (see below)
correct I don’t know when she did her homework.
correct I don’t know when she finished her homework.
wrong I don’t know when she has done her homework.

Note that there is one case where “when + present perfect” can be used: to express surprise or mistrust. Say, a friend of yours told you how he enjoyed the view from the Eiffel Tower, and you weren’t aware of the fact that he had ever been to Paris. You could ask

When have you been to Paris?

It is an expression of surprise. You aren’t really asking when he visited Paris; you express that the fact he did surprised you.

There is another common situation in which the rule can be (seemingly) broken. For example, it is perfectly fine to say:

How many films have you seen this week?
The reason is that “this week” is not a point in the past (even though it includes days which are in the past); it is a period of time containing the present moment. The present perfect in such a situation implies “so far”: “How many films have you seen so far (up until now) if you only count days containing this week?”

The present perfect can be used with any period that includes the present. This includes the common adverbs students learn to use with the present perfect, e.g. “ever” (“from the beginning of the universe until now”), “never” (“not ever”), “already”/“yet” (“from some implied point in the past until now”), for example:

Have you done it yet?
I have never been there.

This article was based on my guide to the most common mistakes in English, which explains many similar topics. Why don’t you check it out?