Sailors have learned to use the stars and the magnetic compass for this purpose.
(Sailors; have learned; to use the stars and the magnetic compass for this purpose) Context(Sailors have learned,List([0, 20))):(Sailors; have learned to use; the stars and the magnetic compass for this purpose)
Sailors have learned,List([0, 20))
Sailors Sailors
have learned have learned to use
to use the stars and the magnetic compass for this purpose
the stars and the magnetic compass for this purpose