Complex sentence: Three British tanks were successfully tested for cross-country ability at the small proving ground near Moscow on Poklonnaya Hill in January 1931, also one tank hull was tested for gunfire resistance in August 1931.
Split into simpler sentences: Three British tanks were successfully tested for cross-country ability at the small proving ground near Moscow on Poklonnaya Hill in January 1931. One tank hull was tested for gunfire resistance in August 1931.