PRESENT PERFECT SIMPLE

To begin with, we can revise the PRESENT PERFECT SIMPLE by watching these two episodes of That's English so that we can talk about our past experiences.

Do you know the difference between 'meeting' and 'reunion'? And what about 'gathering'?

A meeting is any kind of gathering of people, a reunion is a meeting where people get back together. For example a school reunion, where former students meet up again after they have left school.

A meeting is an assembly of people, either by chance or by prior arrangement. This is the most generic term that covers the coming together of two or more people. A gathering is a meeting or an assembly held especially for a social or festive purpose (e.g. a family gathering).

And here's a most completed explanation provided by BBC Learning English.