Most alternative technologies work best on a small scale.大多数替代性技术小规模使用效果最佳。The subject of alternative medical care for older people has been entirely unexplored.尚未有人就替代性老年人医疗保健这一问题做彻底研究。The use of an alternative fuel is not technically feasible.使用替代性燃料在技术上行不通。