【简答题】Without proper planning, tourism can cause problems. For example, too many tourists can crowd public places that are also enjoyed by the inhabitants of a country. If tourists create too much traffic, ...
【简答题】图样中,尺寸线和尺寸界线用( ) 线 画出。
【单选题】图样中,尺寸线 和 尺寸界线用 画出 。
【判断题】191GXGZ.运量小、允许速度低的线路或在隧道内、桥梁上和车站内受建筑物限制时,可酌情低道床厚度,但正线木枕地段碎石道床厚度不得小于200mm,混凝土枕地段不得小于300mm。