两层公共汽车

新干线 E 系双层电车的空调系统

Double blade sword,A Double-edged Sword,A Two-Edged Sword,Two-sided Sword

double standard

double magnet gun

Closure of enterostomy or Colostomy （loop or double-barrel ）

double vagina

double exposure holography

homopolymers of aliphatic hydrocarbons, unsaturated having three or more double bonds

double-acting