Complex sentence: Nevertheless, by September 1939 roughly 250 had found their way into military service: with losses of cars at the frontier mounting, Citroën received army orders for a further 570 between February and May 1940, and further deliveries probably took place before military defeat intervened.
Split into simpler sentences: Nevertheless, by September 1939 roughly 250 had found their way into military service. With losses of cars at the frontier mounting, Citroën supplied a further 570 to the army between February and May 1940, and subsequent deliveries probably took place before military defeat intervened.