The problem came about suddenly.

Suddenly, it started to rain.

He suddenly stood up.

It started raining all of a sudden.

Can you answer this question?

A gap is created in the wall of the building due to the earthquake.

That disease is caused by a mutation.

A new approach is needed to solve this set of problems.

The main problem with this project is the lack of communication.

This question text is too difficult, it's hard to understand.