It is 9:15 a.m. and Virginia Layman's first-year Russian class at Alexandria's T.C. Williams High School is being taught in the Russian language by a Soviet citizen about Soviet schools.

Valerie Ponomarev, genial and energetic, is all over the classroom, asking questions, correcting responses, lecturing on the typical Soviet high school curriculum.

"Do you understand Russian, Dimitri?" he asks 16-year-old Michael Fitzgerald in that language. "Liza," he says, turning to Elisabeth Orshansky, "ask Dimitri if he understands Russian."

She does so perfectly. Fitzgerald answers the same.

Later, in a teachers' lounge, Ponomarev sighed. "They are so much more relaxed than our students," he said. "They sit like this": he slumps low in his chair and drapes one leg and one arm on a table. "But they catch on quickly, so maybe this leisurely way is something we should try."

Ponomarev has six more weeks to deal with the relaxed ways of American teen-agers. As part of a 10-week teaching exchange at T.C. Williams, he helps teach two Russian language classes and lectures occasionally to classes in history, English, social studies and government.

There was a time when such an exchange might have been impossible because of tensions between the two nations. Now, the presence of a Soviet citizen teaching at T.C. Williams has been accepted as part of routine operations.

Ponomarev, who had hoped to be assigned to an American teachers' college, is one of six Soviet teachers teaching in the United States in the exchange program. All arrived here a month ago. The others are at high schools in Connecticut, Illinois, Oregon and New Hampshire.

For the past decade, the American Field Service has sponsored annual exchanges of a half-dozen Soviet and American teachers. This is the first time one of the Soviet teachers has taught high school in the Washington area, according to Layman, who teaches Russian and French at T.C. Williams.

"I guess I haven't thought about it one way or the other," said Lorretta Glover, whose son Anthony is in a second-level Russian language class at the school. She says that her son "is quite interested in Russian and I guess this teacher knows more about it than any teacher from around here."

Ponomarev said the level of acceptance was unexpected. "Everyone has been very nice to me. That is the biggest thing I did not expect."

That does not mean students here have spared Ponomarev from what he terms "embarrassing questions" -- about the Soviet invasion of Afghanistan, martial law in Poland and the defection of Soviet citizens to the United States.

"I am a teacher, not a political person," he said. "When they ask me such questions I tell them to write to the Soviet embassy here in Washington."

"I look to them, the teachers, to help me out of the embarrassing questions," said Ponomarev smiling. Russian "students know much more about life in the United States than students here know about our life."

Ponomarev, 42, said he is not accustomed to teen-agers of any nationality. In his native Kiev, where he lives with his wife and 3-year-old son, he teaches an English teaching class at a teachers' college where everyone is 20 or older. It was there he learned about the exchange program sponsored by AFS, which has sponsored foreign exchange high school students for 30 years.

"Everyone wanted to go," he said of his colleagues, "but there were restrictions of a sort. They the teachers' college wanted to send someone not too young and not too old. Men were given preference, of course -- most of the women had children they could not leave for 10 weeks."

Ponomarev is staying with Kevin and Anne Heanue of Alexandria, whose daughter studied Russian at T.C. Williams before graduating last year.

"The difference between our high schools and yours is very great," he said, as he leaned back in his chair and frowned. Impressed with the sprawling campus of Alexandria's only public high school, Ponomarev said he is surprised at how quiet, peaceful and clean it is.

He said he is troubled that so few American students choose to learn the Russian language. In the Soviet Union, all high school students are required to learn a language, and almost all of them opt for English, he said.

Russian "students are much more curious about the United States," said Ponomarev. "Here, the students are interested, but they do not seem to really care about life in the Soviet Union . They are untouched by it."

The difference in attitudes of the students toward learning is also striking, he said. "It is in the way they answer a question, or sit," he explained. "Our students sit up straight and answer respectfully. They are more disciplined."

Nonetheless, Ponomarev said, his Alexandria students are no better or less educated than their Soviet counterparts.

"They are good students," he said. "They ask many, many questions." graphics 1&2: Photos by HARRY NALTCHAYAN--TWP Valerie Ponomarev says Americans catch on fast and are more relaxed than Russian teens "so maybe this leisurely way is something we should try." Exchange teacher Valerie Ponomarev chats with Virginia Layman, who also teaches Russian.