Complex sentence: The raids failed to divert RAF fighters from France, and by flying at low altitudes, the German bombers could be picked out by searchlights and two were shot down in June by anti-aircraft guns.
Split into simpler sentences: The raids failed to divert RAF fighters from France, and by flying at low altitudes, it was possible for the defences to detect German bombers with searchlights. Two were shot down in June by anti-aircraft guns.