264. The invention of the coal-burning_______engine revolutionized industrial production in the 18th century and opened the way to the development of mechanized transport by rail and sea.
二、知识运用(共两节, 满分45分)
第一节:单项填空(共15小题,每小题1分,满分15分)
从每题所给的A、B、C、D四个选项中,选出可以填入空白处的最佳选项。
21.Besides the others, there was still____third one who said he was second to reach the end.
A.a; a B.a; the C.the; the D.the; a