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That will help to prevent the situation worsening

Several studies show that drinking coffee helps to prevent some illnesses.

to prevent accidents/crime

You should make sure the leg is supported to prevent unnecessary movement.

They couldn't do anything to prevent the problem.

It's better to prevent than to cure.

Because of the war they had to leave the country.

During the night hours we cannot entertain our guests and they have to leave the camping-ground.

to leave the workplace

I decided to leave.