A、To give his feet additional protection from the cold. B、To make the sandals wear-resisting. C、To match his trousers. D、To make

Ancient man, living in colder climates, is credited with making the first shoes, by adding material to the top of the crude "sandals" his neighbors in warmer climates had invented. He did so out of necessity, to give his feet additional protection from the cold.
    Early man, in warmer climates, invented the sandal to protect his feet from sharp rocks, and did so by strapping a mat of woven grass, a strip of animal hide, or a slab of flat wood to his feet with "thongs" he cut out of animal hide. Some even pulled the thongs between the toes and tied them around the ankles to tighten the fit of these crude sandals.
    Wealthy ancient Egyptians wore sandals as long as 5,000 years ago, eventually everyone began wearing them, and the Egyptians designed differently. Ancient Greeks invented the boot, by replacing the sandal’s thongs with solid leather. Many of these crude shoes have endured and are still worn today. Common examples include the sandals the ancient Greeks and Romans wore, the moccasins American Indians wore, and the clogs people in Holland still wear.
    In the Middle Ages, around the time the Crusades began, modem shoes appeared on the scene. The Crusaders, who went on long treks, needed durable, comfortable shoes that people then began making for this purpose.