duorail

例句：

1. 1.The double doors open to the garden.
   双开门通向花园。
2. 2. She has a double life as a doctor and a teacher.
   她既是医生又是教师，过着双重生活。
3. 3. The double-decker bus is very popular in this city.
   双层公交车在这个城市非常受欢迎。