Translation:We did not walk. We ran.
The overlap between English tense and Klingon aspect is complicated. Basically the unmarked Klingon verb should not be used to indicate that an activity is currently ongoing. But there are situations where a Klingon speaker might use the unmarked verb and an English speaker would use the present progressive (-ing). However, because of some of the limitations of the Duolingo platform as a teaching tool, the contributors to this course have decided to use a not fully accurate equivalence of Klingon aspect to certain English compound tenses. So in this course, you must use Klingon -taH or -lI' to get English "-ing" and vice-versa.