If I were

(1) 傳統的文法書，都說虛擬式（subjunctive mood）要用If I were…，例如：

If I were you, I would buy the watch.
如果我是你的話，我會買下那隻表。
(2) 學生宜按照傳統文法書的規矩造句。
(3) 不過，現在部分西人常用If I was…來代替If I were…，例如：

If I was [were] there, I would speak on her behalf.

如果我在那裏，我會代表她講話。
(4) 學者Leech說，現在經常（雖非通常）用was來代替were；但在下列結構中，仍須用were而不可用was：

If I were you…
As it were…

If it were not for…