残油

例句：

1. 1. The engine has a lot of residual oil left over from the last service.
   发动机上还剩下很多上次服务后剩下的油。
2. 2. The old car had a lot of residual oil in the engine.
   旧车引擎里有很多残留的油。
3. 3. The mechanic cleaned out the engine and removed all the residual oil.
   机械师清理了引擎，并清除了所有残留的油。