BEFORE I WENT OUT FOR A WALK, I HAD PREPARED MY LESSONS.A. AFTER I...
15. Before I went out for a walk, I had prepared my lessons.A. After I had prepared my lessons, I had gone out for a walk. B. After I had prepared my lessons, I went out for a walk. C. After I prepared my lessons, I went out for a walk.D. After I prepared my lessons, I had gone out for a walk.