Continuous vs. Continual

Continuous
Continuing to happen or exist without stopping or without being interrupted.

- There is a continuous flow of phone calls/traffic on this road.
- Residents report that they heard Continuous gunfire.
- The change was gradual but by no means steady and Continuous.

Continual
1- Occurring all the time and without interruption.

- The school has been in continual use since 1990.
- They felt continual pressure to perform well.
- Despite continual pain,he refused all drugs.

2- Repeatedly occurring,happening again and again, often in an annoying and inconvenient way.

- There have been continual demands for actions by the political authorities to end the situation.
- The continual buzz of planes overhead.
- Please stop your continual questions.

Continual can only be used in front of a noun.Continuous can be used either in front of a noun or a verb.
Continual is used when something happens many times especially something undesirable :

- There were continual interruptions all day.
- It was sad to see her the victim of continual pain.

- Notice that it is wrong to use continuous to describe things which happen repeatedly.