Complex sentence: The home guard with the help of the regular army set up barbed wire entanglements at local beaches.Beause rumours of submarines were rife in 1941 the local home guard platoon had an exercise to walk from Mangere to Bucklands Beach.
Split into simpler sentences: The home guard with the help of the regular army set up barbed wire entanglements at local beaches. In 1941 the local home guard platoon had an exercise to walk from Mangere to Bucklands Beach.