In Functional Sentence Perspective , Jan Firbas says, "it is worth noticing that an English adverb of indefinite time that has been framed in could be more readily rendered into Czech by an aspectual verb form than one that occurs outside the frame, serving as a setting or a specification".
V lete chodival na dlouhe prochazky.
He usually went for long walks in summer.V lete chodival na dlouhe prochazky.