Beyoncé 的歌詞中 "If I were a boy".如果我是個男孩，就是這樣一個句型。
1.I wouldn’t wear a sweater in such hot weather if I were you.
2.If I were you,I would explain to Jack what happened.
3.If I were you, I should get another lawyer.
4.I would think about it very carefully, if I were you.
在虛擬語氣中我們通常用：If I were...,I would...句型
Eg：1.If I were you, I would study harder.
2.If I were you, I would stop doing that.
3.If I were you, I would go to the doctor.
1.I would study harder if I were you.
2.I would be more careful if I were you.
3.I wouldn't do that if I were you.
IF + I / HE / SHE / IT + WERE
Eg：1.If I were you, I wouldn't play with fire.
2.If you were me,would you study English or go to the movie?
3.If he were taller, he'd be accepted into the team.
*三.在虛擬語氣中，如果要表示“我要是你”，通常是用 If I were you 的，但可以用 If was you 嗎？
首先if I was這個句子語法上沒錯，但并不是虛擬語氣了，而是陳述語氣;
Eg：1.If I was sick, she would give me medicine that tasted terrible.
2.If I were sick, I wouldn't be here.
有的語法學家認為 If I were you 不能說成 If I was you。比如《朗文英語語法》在14.13.2節就認為在 If I were you / If I were in your position 中不用 was。該書所給例句為：
Eg：If I were you / in your position, I’d accept their offer.
但事實上，日常日常口頭表達中也有些英語母語者會用“If I was”.
建議：如果是初學者或作為學生參加考試，以用 If I were you 為宜。
虛擬語氣用在與現在事實相反條件句中時，條件從句的謂語用動詞的過去式 （be的過去式用were），結果主句的謂語用should(第一人稱)或would(第二、三人稱)＋動詞原形。if 表示“如果”，I “我”，were是"are"的過去式，you”你”，would在這里是"will "的過去式，這里的過去式表示的都是假設，不可能發生的事情。
Eg：1.If I were stronger,I would train for the marathon.
2.If I were an animal,I would be a lion.
3.If I I were in charge,I would give everyone a vacation.
4.If I were you,I would not buy that dress.
5.If I were you,I would study English and find a new job.
6.I'd think twice before buying that car if I were you.