When a beach is flanked by rocky points, wave energy is concentrated on the points, causing erosion there, but allowing sand to build up in the area between them.
(a beach; is flanked; by rocky points) (wave energy; is concentrated; on the points; causing erosion there, but allowing sand to build up in the area between them; T:When a beach is flanked by rocky points)
a beach wave energy
is flanked is concentrated
by rocky points
on the points causing erosion there, but allowing sand to build up in the area between them T:When a beach is flanked by rocky points