(Topic sentence missing) Eric exercised each day for eight years to strengthen his muscles. S ometimes he rode his bicycle 100 miles a day! I n addition, he lifted weights, roller-skated (滑冰) , and “ duck walked ” for miles. H e spent hours speed skating (速滑) each day. A ll his years of hard work paid off (有成效) when he won five gold medals for speed skating in the 1980 Winter Olympics.