The meeting that you have missed yesterday was very important.
The girl who is making a speech right now is our monitor.
The vase that I broke yesterday was very expensive.
The boy who helped you yesterday is my neighbour.
That's just the topic that I'm very interested in.
He is just the boss who gave me that valueable opportunity.
This is the topic/theme that I'm tired of.
He is the teacher who helped me.
We all like that speaker who is very humourous.
The old lady whose two daughters are both teachers is our neighbour.