Present Perfect is a very confusing English tense for many Russian speakers. There are many times when you can use another tense, usually past simple, but there are times when the use of present perfect is essential. We use this tense to talk about life experience and the time it was completed isn’t important; this activity could have been completed at any time — from birth until the moment just before speaking — but the important past is that it is done. So let’s look at some examples:
Person 1: Have you been to a foreign country? (Experience is important, not the time)
Person 2: I’ve been to Germany. (The completion of the action is important, not the time)
Blake has run in four marathons. (Here, the action was completed four times. That is the focus, not the time)
If you want to mention when something happened, you have to use Past Simple; never state when an activity was completed when using Present Perfect. This is true even if the time period is understood but not explicitly stated. For example, if your teacher asks you what you did over the weekend, you should use past simple because the time period is known. Unfortunately, as with all things in English, there is an exception, and this rule is no exception. If you want to emphasize that the activity was recently finished, you’ll use Present Perfect.
Teacher: Did you all do your homework?
Student 1: Yes, I did it this weekend.
Student 2: Yes, I’ve just finished it!
Another exception is unfinished time periods, i.e. today, this week, this month, this year, this century. When we talk about the number of times an action has been completed in an unfinished time period, present perfect is also used. Let’s look at Blake again:
Blake has run in four marathons this year.
We are emphasizing the number of times an activity has been completed from January 1st until right now. If we used Past Simple, it would indicate that Blake doesn’t plan on running in any more marathons until next year.
I hope this brief overview helps you all in using this tense. And as I told some students recently, don’t be afraid of using it. Practice and correction will help you to understand the rules and nuances much better than just studying. Good luck!