The greatest road system built in the America prior to the arrival of Christopher Columbus was the Incan highway,which,over 2,500 miles long and extending from northern Ecuador through Peru to Southern Chile.
B Columbus was the Incan highway,over 2,500 miles in length,and etended
E Columbus,the Incan highway was over 2,500 miles long,extending
hmm...可是如果"The greatest road system built in the Americas prior to the arrival of Christopher Columbus"是"the Incan highway"的同位語, 那麼 The greatest road system built in the Americas prior to the arrival of Christopher Columbus extended over 2,500 miles long and extending from northern Ecuador through Peru to Southern Chile. 跟 The Incan highway extended over 2,500 miles long and extending from northern Ecuador through Peru to Southern Chile. 好像沒什麼區別?