如果我是你... C to Eng

If I were you <------------------Conditional type 2--未發生 ; unlikely to happen or impossible things.
If I were Andy Lau <--------Impossible
http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/2cond.htm( Here is a link for you.)
You can say
如果我是你, 我絕不會這樣做.
If I were you, I would NEVER do that/this. ( not happened yet)
Usually we say " to do THAT".
were ---------------- would <------Correct!
_were --------------will <--------Wrong!_____________________________
If the event is over and you want to talk about this PAST過去的 event.....
Conditional of type 3 for comments on past events( something like
馬後砲 in Cantonese.)
If I had been you, I would NEVER have done that/this.

That's it.
8686868686886868686

I wouldn't do that if I were you.

If I were you, I will never do this.

The correct translation is -

I wouldn't have done that if I were you.

「如果…」，那是假設了。英文文法有 subjunctive Mood 的，那麼 If I were you，也是 Idiomatic 的說法呢。
我以為 If I had been you, I would not have done this. 是正式的說法。但 以 idiomatic English 來說，你可說：If I were you, I would not have done this.的。

2009-02-09 07:40:44 補充：
我了解句子所指，是已成過去。也以同樣形式提供了！

2009-02-12 11:30:29 補充：
剛剛看到投票的結果：答非所問者得票最多，也使人心死的呢！

2009-02-12 11:47:28 補充：
為甚麼沒有人提及英文文法的 Mood 的問題呢？
If I were you 是英語 Mood的最簡單之一的例子了。
凡讀英語，我以為都應知何謂 subjunctive mood 的。為甚麼今天這就成問題了？

If i were you,i will not do that.

你可以試下用呢個網:

http://babelfish.yahoo.com/translate_txt

If I were you, I absolutely will not do that.

If I am you, I will not do this.

if i were you, i would not do this/behave like this...