When you keep someone from doing something you prevent that person from performing an action.
He had a very good lawyer. She kept him from going to jail.
I can’t keep myself from eating candy.
Oh, I see it is 6:30 already. I don’t want to keep you from dinner.
To keep someone in means to not allow that person to go outside.
Her son had a bad cold. His mother kept him in for five days.
Keep off can mean to not walk on something or to stay away from an area.
I want you to keep off my property.
He tries to keep off the highway in bad weather.
Keep someone off can also mean to prevent someone from being somewhere.
Her injuries kept her off the soccer field.
They kept him off the plane because he was drunk.
If you keep off a subject, it means you avoid talking about that subject.
She is a very private person. I keep off the subject of her divorce.
My finances are none of your business. Let’s just keep off that subject.
Lastly, if you keep off something that can enter your body like food or drink or drugs,
that means you don’t let it into your body.
Pregnant women should keep off alcohol.
I have kept off cigarettes for over thirty years.
Keep on means to continue with something. Very often, you can just use keep to
express the same idea.
I don’t trust you. You keep on lying to me.
You keep lying to me.
She kept on changing her mind.
She kept changing her mind.
Keep on can be used by itself to mean continue if the action has already been mentioned.
I asked her to stop nagging me. But she just kept on.
Keep out means to prevent someone or something from entering.
We closed the curtains to keep out the sunlight.
We closed the curtains to keep the sunlight out.
There was a sign on the fence around the transmitter tower. The sign said “Danger. Keep out.”
KEEP OUT OF
Keep out of means not to get involved.
My mother and brother were yelling at each other. I kept out of it.
His neighborhood is very tough. Somehow he keeps out of trouble.
When you keep to a plan or keep to a path that means you are continuing to do what
you started out doing.
I don’t care if people have been out sick. We have to keep to the schedule.
They kept to the side of the road.
If you keep up someone, it means you are preventing them from going to bed.
The TV program kept us up until midnight.
I’ll be reading for a while, but you can go to bed if you’re tired. Don’t let me keep you up.
Keep up can also mean to continue an action.
Your grades have been excellent. Keep up the good work.
KEEP UP WITH
When you keep up with someone, that means you are near someone who is somehow in motion and you are able to move at the same speed.
My friend was walking so fast. I couldn’t keep up with her.
He talks so fast. It’s hard to keep up with him.
When you keep up with something, that can mean you are staying informed about it.
I try to keep up with the news.
Keep up with can mean to continue an activity.
She is seven months pregnant. Still, she keeps up with her exercises.