有言在先 meaning in English

make clear beforehand; forewarn; have agreed before; having previously pledged one's word; let it be clearly understood before-hand

Anything but his death, i told you from the first .
我对你有言在先，别的怎么都行，就是不要他死。
But i warn you , i want to be free to do whatever i choose , without having to tell you anything about the life i lead
“我有言在先，只要我喜欢，我要怎么着就怎么着，我不会把我的生活琐事告诉您的。
But despite a warning that “ there is a good deal of science in the book , as much as can be accommodated without the machinery of equations ” , the story neglects the physics
但是，尽管有言在先“本书通篇以科学为要，兼容并包而（对各门学科）未加平衡” ，物理学还是被忽略了。
Before commencing , it is but fair to warn you that the story will sound somewhat hackneyed in your ears ; but stale details often regain a degree of freshness when they pass through new lips
开场之前，我有言在先，这个故事在你的耳朵听来恐怕有些陈腐，但是过时的细节从另一张嘴里吐出来，常常又会获得某种程度的新鲜感。