Complex sentence: Halberstadt built 700 CL.IIs until being replaced in production by the improved Halberstadt CL.IV in mid 1918, with a further 200 built in 1918 by the Bayerische Flugzugwerke (BFW).
Split into simpler sentences: Halberstadt built 700 CL.IIs by the time production shifted to the improved Halberstadt CL.IV in mid 1918. A further 200 CL.II aircraft were built in 1918 by the Bayerische Flugzugwerke (BFW).