We're learning how to translate the Dutch present perfect, and whether we have to translate it to one English tense or another. Sometimes we have the choice to use either English present perfect or simple past (and then both should be accepted by Duo), but often we are forced by English grammar rules to use one but can't use the other, for example by using an adverb of time:
I have played with the dog today / this week.
I played with the dog yesterday / last week.
Or, to look at it the other way, we're learning that both of these English tenses are translated into Dutch present perfect.