The boulders at the front of the glacier gouge the valley floor, carving it into a U-shaped trough.
(The boulders at the front of the glacier; gouge; the valley floor; carving it into a U-shaped trough) Context(The boulders at the front of the glacier gouge,List([0, 46))):(The boulders at the front of the glacier; gouge the valley floor carving; it; into a U-shaped trough)
The boulders at the front of the glacier gouge,List([0, 46))
The boulders at the front of the glacier The boulders at the front of the glacier
gouge gouge the valley floor carving
the valley floor carving it into a U-shaped trough
it into a U-shaped trough