Present Perfect in english.
I HAVE STUDIED english recently = Eu ESTUDEI inglês recentemente.
Dificilmente um nativo (brasileiro) vai dizer "eu tenho estudado inglês recentemente".
Se ele continua estudando, o presente seria, "eu ESTUDO inglês" .
Não estuda, o Passado: "eu ESTUDAVA inglês"
doesn't sound weird at all, remember "The times they are a-changing," though that's a rustic dialect. Still the usage of continuous is perfectly fine. The sense is that it's recent and still may be going on, whereas things have changed refers to changes that are finished.
I don't know when to use the verb in the past or in the continuous form... For example, I answered this question at that way: "Things have been changed" instead "Things have been changing". So, the right answer was the verb in the continuous form , but in another exercises the right answer were with verb in the past. It's hard to understand. I'm getting confused... lol Somebody would help me with my doubt? I'm grateful since already. ps: As you can notice, I'm not a native speaker of English, so I ask you to excuse my mistakes.
This is a Portuguese quirk. It would be straightforward if "ter (present tense) + past participle" matched the English present perfect but it doesn't. A lot of typing has been devoted to this mismatch. See Danmoller's mention of the "pretérito perfeito composto" here:
and the much longer discussion here:
It is tempting to always translate Duolingo's simple sentences using the present perfect continuous, but things are complicated by the fact that some English verbs cannot be written in continuous form so various workarounds are needed. Good luck, don't despair, we are all in the same boat. :-)
[Update: Danmoller has written more on the topic here: https://www.duolingo.com/comment/12292400 ]