The phrase "a guard to keep" is correct and usable in written English.
It can be used when referring to a protective measure or a person assigned to maintain security or safety.
Example: "The castle had a guard to keep watch over the entrance during the night."
Alternatives: "a protector to maintain" or "a sentinel to ensure".
The next gallery, filled mostly with Caravaggio and his followers, is never crowded, even with my failure to enlist a guard to keep people out.
Dr. Michael V. McGill, school superintendent, said the school is trying to determine how to handle residents' complaints, while weighing them against the instinct to be accommodating and avoiding the legal difficulty of posting a guard to keep people out.
It may simply be a matter of providing fall protection, or installing a guard to keep hands out of machines.
The suspension is rock-hard; I wished I'd brought a mouth guard to keep my teeth from chattering.
Southampton Town police officers broke up a weekend-long prom party at a Hampton Bays rental house on May 24, rounding up 31 underage drinkers who had hired a security guard to keep out crashers.
"There was an underground tunnel that kids had to use to walk to school and several of us tried to get a crossing guard to keep the kids safe.
Holy Family turned to a sophomore guard to keep the Gaels heading down the right path.
The Bulgarians disposed a strong guard to keep the pass safe.
The crown was given to a U.S. Army unit by a Hungarian honour guard to keep it from being seized by advancing Soviet troops after World War II.
But the Knicks would still need a top point guard to keep Anthony and Amar'e Stoudemire humming, and Billups would be the best one on the market.
Yes, I used style judgments as a psychic sneeze guard to keep other people in their place, as she helpfully pointed out, many times.
