Complex sentence: The 46th Infantry Division was part of the British Expeditionary Force sent to France in 1940 as a labour and training unit but ended up fighting in the retreat to Dunkirk and evacuation to Britain.
Split into simpler sentences: The 46th Infantry Division was part of the British Expeditionary Force sent to France in 1940. It was assigned as a labour and training unit, but ended up fighting in the retreat to Dunkirk and the evacuation to Britain.