But I have promised to keep， and miles to go before I sleep。

刚刚才明白这句话的语法结构，在涉足荒野的电影里，这句话被翻译为：但我已有约定，沉醉前还有一段路要走。

原文来自一首诗，被翻译成：

但我有许多诺言不能违背
还要赶多少路才能安睡

全诗:

Stopping by Woods on a Snowy Evening

                   ---By Robert Frost

Whose woods these are I think I know
His house is in the village though
He will not see me stopping here
To watch his woods fill up with snow

My little horse must think it queer
To stop without a farmhouse near
Between the woods and frozen lake
The darkest evening of the year

He hives his harness bells a shake
To ask if there is some mistake
The only other sound's the sweep
Of easy wind and downy flake

The woods are lovely, dark and deep
But I have promises to keep
And miles to go before I sleep
And miles to go before I sleep

《雪夜林边小立》
----罗伯特·弗罗斯特
我想我认识树林的主人
他家住在林边的农村
他不会看见我暂停此地
欣赏他披上雪装的树林

我的小马准抱着个疑团
干嘛停在这儿 不见人烟
在一年中最黑的晚上
停在树林和冰湖之间

它摇了摇颈上的铃铎
想问问主人有没有弄错
除此之外唯一的声音
是风飘绒雪轻轻拂过

树林真可爱 既深又黑
但我有许多诺言不能违背
还要赶多少路才能安睡
还要赶多少路才能安睡