The study looked at how English speakers learn to use the Spanish Imperfect tense. They found that even advanced learners struggle to use it correctly for different meanings like habits or ongoing actions. English speakers tend to use the wrong tense (Preterit) in some situations where Spanish requires the Imperfect. This shows that learning to use the Imperfect in Spanish is tricky for English speakers because they have to reassemble their understanding of how verb tenses work.