An extension is a new room or building that is added to an existing building or group of buildings. (已有建筑或建筑群的) 延伸建筑
noun [抽象名词] 延伸，扩展；展期，延长期；扩建部分，延伸部分；（电话）分机；扩展名；（为非全日制学生开设的）进修部；牵伸（术）；外延；广延（性）
An extension is a new section of a road or railway that is added to an existing road or railway. (已有公路、铁路的) 延长路段
后缀: sion
【noun】 表示某种行为、状态或结果 - indicating an action, state, or result
原词: extension
是通过后缀 【sion】 构成的派生词
