Complex sentence: The survivors saw that the way through Ginchy and Lesbœufs was open to the British but by evening reinforcements had arrived and closed the gap either side of Foureaux (High) Wood.
Split into simpler sentences: The survivors saw that the way through Ginchy and Lesbœufs was open to the British. By evening reinforcements had arrived and closed the gap either side of Foureaux (High) Wood.