有一读者问： 在一本书中遇到这样的话：
(1)How do you set about getting married? If you've got to in a hurry?
第二个问题是什么意思？ if从句怎能独立运用呢？
第二个问题在此是第一个问题的补充。其含义是： 如果你急忙要结婚的话，你如何着手安排呢？ if常可引导一个独立的从句，再如：
(2)Well, if it isn't Spicey? （如果不是Spicey干的呢？）
(3)If Branson and company come across it? （假如被Branson一伙发现了呢？）
下面两句中的许可相当于“是否”：
(4)— And now, if I may go to your house?
— Right through the door there, miss, and to your left.
(5)— John. If you are going to start on me.
— I'm not going to spare you.
独立的if从句亦可表请求（后接will），例：
(6)If you will sign here.
(7)If somebody'll come here and sit with him.
独立的if从句也可表感叹，常用虚拟语气表“但愿”，例：
(8)If I only knew!
但也可表“但愿不”，例：
(9)If he had caught me!
