2·Tourists should appeal to related departments and preserve the scene of the accident and material evidence when an accident occurs.
游园时发生安全事故时，应及时求助相关部门，并保护好现场和物证；
3·Leaders of the Chadian rebel movement say it never occurred, while nomads, after two years of scratching around in the area, have still not found a single cartridge case or other material evidence.
乍得反叛运动的领导人说那些事从来没发生过，游牧人在那个区域搜索两年仍然没有发现一个弹壳或是其他物证。