As a glacier travels across a terrane it often will scour former river valleys, changing their typical V-shape to a U-shape which is typical of glaciers.
(a glacier; travels; across a terrane) (it; will scour; former river valleys; T:often) (a U-shape; is; typical of glaciers)
a glacier it a U-shape
travels will scour is
across a terrane
former river valleys T:often
typical of glaciers