Complex sentence: Holt tractors had become successful in West coast logging and farming industries, and used similar technology to that which William Foster & Co. of England built the Mark I tanks for theBritish Army in the First World War.
Split into simpler sentences: Holt tractors had become successful in West coast logging and farming industries. They used technology similar to that which William Foster & Co. of England used to build the Mark I tanks for the British Army in the First World War.