that or if

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hi everybody,

(Source:Murphy’s English Grammar)
I am sorry for any trouble I have caused.

that or if:
I am sorry for any trouble that I have caused.
I am sorry for any trouble if I have caused.

Thanks in advance

2

That is correct.

#1. I am sorry for any trouble that I have caused. = I am sorry for any I-have-caused trouble.
#2. *I am sorry for any trouble if I have caused. < I am sorry for any trouble if I have caused it.