"I am doing an investigation."
Translation:Yo estoy haciendo una investigación.
Hago is simple present tense (I do), this is a lesson on the use of the gerund in, among other constructions, the present progressive/continuous tense (I am doing). While we use the latter more in English than in Spanish, in both languages the meanings are slightly different. Present progressive implies continuing action, being done now in the broad sense present simple implies repeated action, not necessarily done at this moment. (I am doing the dishes now, I do the dishes every morning (but this is the afternoon)) 03-9-14
I finished the Spanish tree a long time ago, but I do three "strengthening" exercises per day to keep it gold. As a result, I do not encounter these as part of one lesson or another. Anyway, I reported the error weeks ago, and I believe they already notified me it was corrected.