A condition clause is usually a sentence with ‘if’ or ‘unless’ in. Simple as that. But getting its rules wrong can make you look unprofessional.
We use the conditional clause surprisingly often. Most notably, we say ‘if I were you…’
Or, as some would have it, ‘if I was you…’ But the latter is simply wrong.
Simple things to remember:
If something is a fact, use ‘was.’ For example, ‘when I was nineteen, I started this blog.’ Because I did start my blog when I was nineteen.
But if something is speculative (a different situation to the one you’re in), use ‘were.’ So it’s always, “if I were you” – because you never will be somebody else… unless Freaky Friday turns out to be a documentary.
It’s an important part of everyday speech and copy. Get it right, and nobody will notice. Get it wrong, and everyone will.
FURTHER READING… My Grammar and I (or Should That Be ‘Me’?) By Caroline Taggart and J. A. Wines.