Complex sentence: Belgian General Headquarters chose Halen as a place to delay the advance and make time to complete an orderly retreat towards the west and the Belgian Cavalry Division was sent from Sint-Truiden to Budingen and Halen, to extend the Belgian left flank.
Split into simpler sentences: Belgian General Headquarters chose Halen as a place to delay the advance and make time to complete an orderly retreat to the west. The Belgian Cavalry Division was sent from Sint-Truiden to Budingen and Halen, to extend the Belgian left flank.