Start with a normal declarative sentence
Reverse the order of the subject and the verb.
Don’t worry about do.
Yo juego fútbol y yo nado en la playa.
The question is saying that Elena attended so it is past tense<span> and because it is referring to Elena it will be el/ella/usted conjugation.
Therefore: it is probably </span><span>asistió which means attended.
It could be ha </span>asistido though because ha <span>asistido means has attended but Elena has attended a conference does not sound as good as Elena attended a conference.
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