锕类任何化学性质相似, 原子序数在89 ( 锕 ) 与103 ( 铹 ) 之间变化的放射性元素.Any of a series of chemically similar, radioactive elements with atomic numbers ranging from 89 ( actinium ) through 103 ( lawrencium )....
在楼房林立的地区降低最高车速限制to reduce the speed limit in built-up areas这座历史名城有着其繁忙的千樯林立的港口.The historic city had its busy ship - filled harbor.在房屋林立的地区,车速限制为每小时30里.We are restricted to a speed of 30 miles an hour in built up areas....