Since the worms prefer to remain near the surface of the soil they will eat their way up through the waste in the bin leaving castings at the bottom.
(the worms; prefer; to remain near the surface of the soil) (the worms; to remain; near the surface of the soil) (they; will eat; their way up through the waste in the bin leaving castings at the bottom) (the bin; leaving; castings; T:at the bottom)
the worms the worms they the bin
prefer to remain will eat leaving
to remain near the surface of the soil
near the surface of the soil
their way up through the waste in the bin leaving castings at the bottom
castings T:at the bottom