1.   A fatal heart attack happens in Britain every three minutes.

2.   A hardware error on the other hand happens in a more or less random way.

3.   A lot can happen in two years.

4.   A programme is not just what happens in the conference hall.

5.   A similar incident happened in the Hartest district of Suffolk.

6.   Airlocks happen in hot water systems for a number of reasons.

7.   All of the eruptions except Krakatoa happened in the northern hemisphere, and together they show a clear pattern of behaviour.

8.   All this has happened in the country that was first to reap the benefits of radical reform.

9.   An improbable event is one that happens only in one or a few possible worlds.