Possible future situations
– The if-clause can be in the beginning or at the end of the sentence.
e.g. If I have a dog, I will look after it.
=
I will look after it, if I have a dog.
– ‘If not’ can be replaced by ‘unless’.
e.g. Unless it rains, I will go to the beach.
= If it doesn’t rain, I will go to the beach.