Complex sentence: The bridge being the only crossing on the river which gave the Eighth Army access to the Catania plain, its capture was expected to speed the British advance and lead to the eventual defeat of the Axis forces in Sicily.
Split into simpler sentences: The bridge being the only crossing on the river which gave the Eighth Army access to the Catania plain. Its capture was expected to speed the British advance and lead to the eventual defeat of the Axis forces in Sicily.