The invention and use of trains marked the beginning of mass tou

The invention and use of trains marked the beginning of mass tourism activities. Jet planes, especially supersonic passenger planes, were put into operation, making large-scale international and intercontinental tourism activities a function.
【正确答案】：火车的发明和使用，标志着大众旅游活动的开始，喷气式飞机，尤其是超音速大型客机投入运行，使大规模的国际间、洲际间的旅游活动成为功能。