In this paragraph, how to understand " clicks its heels, snaps to attention" ? In 1914 Peter Kollwitz is eighteen years old, slogging through the mire with other freshfaced volunteers. Ranks of engineers drag up the artillery. Horsedrawn ammunition columns are whipped towards the front. Offi cers in staff cars stand ramrod tall and bark orders for die große Schlacht, the great battle which will punch through the Allied lines. The Imperial Fourth Army clicks its heels, snaps to attention, stands poised to seize Calais and swing south to Paris. A shrapnel shell bursts overhead, two bivouacs catch fire, a week’s rations go up in smoke, yet wave after wave of young men run on into the thunder, singing as they reach for victory.