sentences:  Seventh Army to regain ground lost to Germany's Operation Nordwind New Year's offensive into Alsace.From 25 January until 16 February 1945, XXI Corps was attached to the French First Army and took part in bitter winter combat that ultimately collapsed the Colmar Pocket.After a period of rest, the corps returned to the front on 28 February 1945 and pushed to the edge of the Siegfried Line during the first week of March, 1945.