Complex sentence: On 19 November, 20 ° "Gruppo" based at Sid el Rezegh suffered heavy losses when British armoured forces (40 Crusaders of 6th RTR and several units of 3rd Brigade, South African Regiment, both part of 7th Armoured Brigade) suddenly attacked the airfield.
Split into simpler sentences: On 19 November, 20 ° "Gruppo" was based at Sid el Rezegh. That day, British armoured forces (40 Crusaders of 6th RTR and several units of 3rd Brigade, South African Regiment, both part of 7th Armoured Brigade) suddenly attacked the airfield.