Complex sentence: By February 1942, production had switched to the Ram II model with a 6-pounder gun and continued until July 1943, following a March 1942 decision was change production over to the automotively-similar adopt M4A1 Sherman tank for all British and Canadian units.
Split into simpler sentences: By February 1942, production had switched to the Ram II model with a 6-pounder gun and continued until July 1943. In March 1942 a decision had been made to change production over to the automotively-similar M4A1 Sherman tank for all British and Canadian units.