He suddenly stood up.

It started raining all of a sudden.

The electricity in my house has been cut off.

He was working late into the night last night.

There is a planned blackout tonight, so please come home early.

That disease is caused by a mutation.

He is majoring in electrical engineering.

Electric baths are a great way for relaxation and promoting health.

He is undergoing electrotherapy for his back pain.

It's difficult to understand the principles of electrooptics.