WITH U.S. FORCES, SAUDI ARABIA -- At the Navy hospital, surgeons do needlepoint to keep their hands supple. Orderlies wrap and unwrap hospital gowns and nurses stop the "bleeding" of artificial wounds.

At the Army missile base, a 1st sergeant holds tournaments -- Ping-Pong, chess, bobbing for apples, anything he can think of to make his men relax. At the airport, a colonel worries about creature comforts, thanks God for the U.S. Mail and tries to answer the unanswerable: When does the war start? What happens next? How long do we stay?

After four months, the answers are as elusive as ever for the more than 250,000 U.S. servicemen and women confronting Iraqi forces in the Arabian desert. Diplomacy seemed to gain the upper hand this week when Iraqi President Saddam Hussein began releasing thousands of foreigners held against their will, but for the soldiers of Operation Desert Shield, little has changed. There still is nothing to do but mark time.

A soldier's boredom is a commander's curse. Idleness dulls the combat edge, undermines confidence and makes people sloppy, Desert Shield commanders say. Soldiers start to worry about their skills and dwell on their misgivings. The overwhelming majority of U.S. service people in Saudi Arabia have never seen combat and wonder if they will measure up.

Many Desert Shield officers and non-commissioned officers acknowledge that, over time, inaction and uncertainty will eclipse homesickness as morale destroyers. The ups and downs of diplomacy only make it worse. Peace suddenly seems possible, but the soldiers came in anticipation of war.

"You're talking about the biggest problems I have," said Navy Capt. Gregg Parker, chief of surgery at the 500-bed Fleet Hospital 5. "It is very difficult emotionally to stay on top. We run a fair number of drills, but even that gets old after awhile."

Field Hospital 5 is a first-of-its-kind medical facility, carted to Saudi Arabia in containers aboard a cargo ship and assembled on land from scratch in 16 days in September. It is fully air conditioned, has 80 doctors, 155 nurses, three operating rooms and an intensive care unit. It can expand to accommodate 1,000 patients whenever needed. Hawkeye's MASH tent could fit into Field Hospital 5's receiving room.

Boredom, and how to beat it, is on every officer's mind. The radiology unit keeps reasonably busy because most of Desert Shield's casualties to date -- from aircraft accidents, car wrecks, sports injuries -- require X-rays. Technicians have taken 2,500 X-rays in three months, a very light load but enough to maintain interest.

For Parker's surgeons, however, maintaining skills is more difficult. He and his 24 colleagues have performed 250 operations in three months, most of them appendectomies, removals of kidney stones and the like. For Parker, chief of surgery at Portsmouth Naval Hospital in Portsmouth, Va., and his team of specialists, this is minor stuff.

"I feel my level of skills going down to a certain extent," Parker said. "But it's only a question of one three-hour procedure to get it back." He said other surgeons hone their dexterity through needlepoint: "It kills time, but it's also good for hand-to-eye coordination."

Keeping busy is the goal. There is make-work: Orderlies fold and refold hospital gowns, calibrate gauges and equipment, check the shelf life of medicines.

And there are drills: Last month, Britain's Desert Rats sent 150 soldiers to Fleet Hospital 5, all of them with simulated wounds. The hospital "treated" them in 90 minutes and was satisfied with the results. Still, it wasn't the real thing. Combat remained the great unknown.

"We don't have a whole lot of people who have seen a lot of trauma," said Lt. Gaylene Barnum, chief nurse at the hospital's receiving room. "I don't think any drill can tell you how it will be when this place is filled up with wounded."

Some drills, however, are more realistic than others. Two weeks ago, Iraqi forces launched a pair of Scuds -- the all-purpose, surface-to-surface missiles that U.S. military officials believe would be used to do everything from destroying airports to delivering poison gas.

The Iraqis apparently were conducting a drill of their own, but the 2nd Patriot Batallion of the 7th Air Patriot missiles, the Army's state-of-the-art anti-aircraft and anti-missile weapons, are the Scuds' chief antagonist.

"We heard there was incoming," said 1st Sgt. Larry Brooks. "You'd have thought it was D-Day here." His soldiers reacted well, however. Fear was forgotten, he said. Everyone took the right combat station; everyone was ready to do battle.

Brooks, a gruff, 36-year-old snuff chewer from Arkansas, was satisfied. He is a prototype Army non-com: eagle-eyed, loud-voiced and profane, but utterly beyond reproach, a big brother to his men. Soldiers' wives in Fort Bliss, Tex., sent him the Christmas stockings for their husbands and others in the unit. He plans to distribute them on Christmas morning.

At first, he said, it was easy. His men were camped in the middle of a remote stretch of desert with an abandoned warehouse to live in and no hot food. Three months of cleaning and carpentry turned it into a reasonable barracks with a cooking shed and enough water for showers.

Now Brooks's favorite thing is tournaments -- chess, Ping-Pong, obstacle-course competitions, running. A bobbing-for-apples contest, he said, "let them get a laugh on the first sergeant."

His worst problem from the beginning was tension, he said, magnified because of inaction, the inhospitable surroundings and the youth of the soldiers, many of whom are only a couple of years out of high school. "The young ones are scared to death," he said. "If I see someone that looks like he might fail, I talk to him, find something he likes to do and put him to work. They'll all make it."

Brooks, for one, is not unhappy about the lack of liquor or night life in Saudi Arabia, a strict Moslem country that forbids consumption of alcohol. "In fact," he said, "it's an asset." Soldiers "don't mess around. They're seeing that there's something in the world besides drinking and hanging out. I'm seeing my men grow up in front of my eyes."

Mail, which comes twice a day most days, is probably the wellspring of morale. At the Air Force's 1703rd Air Refueling Wing, Col. David E. Cormack also talks about "tremendous support" from airmen's hometowns: "We have boxes and boxes of letters addressed to 'any soldier,' most of them from school kids.

Cormack, the wing commander and a Vietnam veteran, has a full wartime contingent to fly and tend his KC-135 tanker aircraft, charged with the in-flight refueling of hundreds of planes operating in Desert Shield. "We've got enough people for hostilities, but we have too many for normal operations," Cormack said. "We work hard on keeping them busy and getting them creature comforts."