"He hecho un descubrimiento."
Translation:I have made a discovery.
Or maybe is the the beginning of "hecho" that is barely pronounced. Regardless, you should expect that when one word ends with the same vowel sound that begins the next word they will tend to get combined in naturally spoken Spanish with no punctuation preventing the combination..
Now, imagine how the sentence, "Va a hablar en español.", sounds. :)
"I made a discovery" carries the same meaning as "I have made a discovery" in English, therefore it shouldn't be considered incorrect. Hecho is necessary in the Spanish sentence, but not in the English translation. Too many Duolingo users compulsively defend the software for no apparent reason, claiming that translations should be either interpretive or completely literal depending on which supports their argument. Translation is an art, not a science.
Maybe it is restricted to "have made" so that people learn to make a difference between "he hecho" (preterito perfecto) and "hiciera" (imperfecto).
Since those two tenses are used in different contexts, it is important to know one from the other. (That's why there's such an awful number of mistakes in my texts!)
The line between the two future tenses "voy a hacer" and "haré" seems softer.
No. Just because 'hacer' can mean 'to make' or 'to do' doesn't mean it can always mean both. Sometimes context only allows one possible translation.
I don't know if English is your native language or not, but "done a discovery" makes absolutely no sense in English.
If you cooked eggs for breakfast yesterday, would you say you made eggs, or did eggs?
You would say "I made some eggs", but if you were a chicken you might say "I laid some eggs".
For the record, another casual, regional usage would be "I fixed eggs." Which begs the (entirely facetious) question: Why is it that when morning has broken, the only thing that gets fixed is breakfast?
It's extremely casual, but not completely unheard of, to use "did" in a case like this.
"What did you do for breakfast this morning?"
"I did eggs on toast."