They argued. They grimaced. They paced. They pounced. But mostly they objected.

"Objection, Your Honor! She's leading the witness," said one.

"Objection! That's hearsay," said another.

"Objection, your honor! Can we approach the bench?" said a third.

They sounded a lot like attorneys yesterday at Fairfax County Circuit Court, but they were actually high school students playing the part of attorneys, as well as jurors, witnesses, bailiffs and clerks. It was all part of the Model Judiciary Program, which gives students an opportunity to learn about the judicial system by staging mock trials in front of real judges.

About 350 students from high schools around the county gathered at the Judicial Center in Fairfax City yesterday. They had been given scripts to learn and had been coached by local lawyers who had donated their time.

With few exceptions (the bailiff in blue jeans, the attorney in Topsiders), it appeared to be a typical work day around the five-story courthouse. The parking spaces filled quickly, and the dialogue that filtered out of the courtrooms sounded all too familiar: "Therefore, we feel that the case should be dismissed . . . . "

In Courtroom 5G, it was Smith v. Jones, a fictitious medical malpractice suit. The case in a nutshell: Kathy Smith's severe stomach pains were misdiagnosed by Dr. Robert Jones as gastritis from eating pizza. The next day, Smith suffered a ruptured appendix. She sued.

As the two teams of lawyers selected a jury and called seven witnesses to the stand, Circuit Court Judge J. Howe Brown Jr. presided in his black robe as though it were a real trial, complete with a 10-minute recess.

Although jittery, the students quickly slipped into their roles, particularly Dan Shanahan, 17, a senior at Woodson High School, who resembled a real-life attorney in a dark suit, white oxford shirt and soft pink tie.

Shanahan: "Objection, Your Honor! She's leading the witness."

Brown: "Sustained."

Shanahan: "Objection, Your Honor! She's still leading the witness."

Brown: "Sustained."

While the four-boy, three-girl jury was deliberating, the judge gave the other students present his verdict of their performance: "outstanding." He also gave them some pointers.

Brown advised the students that they should stand when addressing the court and should not lean on the lectern. He suggested that a student with a soft voice "boom it" and others cut the "uhs" and "okays" out of their speeches.

He also passed on some trade secrets: Never ask a witness a question if you don't know the answer, and when you get the answer you're looking for, stop.

Other judges -- or lawyers filling in as judges -- presided over 10 similar trials being staged around the courthouse. The program has become an annual event and is sponsored by the local and state bar associations and the state YMCA.

Vicki Drinnon, a speech and debate teacher at Lake Braddock High School, said the students became involved in the program to learn about courtroom procedures and their responsibilities as citizens.

Many around the courthouse were impressed.

"It kind of restores your faith in teen-agers," said Fairfax lawyer Charles Maxfield, who coached the plaintiffs in Smith v. Jones. "They're bright, eager to learn, intelligent, hard-working. The type that, frankly, don't make the newspapers."