sentences:  The First Army – already stationed near the Hürtgen Forest – had to carry out the main effort through the Hürtgen Forest toward the Rur River.The Ninth Army had to advance north of the forest through the Rur plains.The British XXX Corps – together with units from the U.S. XIII Corps – had to reduce the Geilenkirchen salient in the north in a different operation named Operation Clipper.