The singer messed up, not the guitarist. (it, who)
It was the singer who messed up, not the guitarist.
You need to practise a lot before performing. (what,do)
What you need to do is to practise a lot before performing.
Taking deep breaths works for me.(what, is)
What works for me is taking deep breaths.
I like acting in public the most. what, is
What I like to do is acting in public the most.
I’m studying music, not theatre. (it’s, that)
It's music that I'm studying, not theatre.
The low salary put me off , not the hours. (it, that)
It's low salary that put me off, not the hours.
