IT IS Sunday afternoon and My Phuong, my Amerasian foster daughter, is upset. Over the phone, a Vietnamese aunt in another part of Northern Virginia has just scolded her for living with Americans. My Phuong should be with her Vietnamese family, the aunt argued; then she hung up.

"Why did she do that?" My Phuong cries. "I just called to say hello."

My wife and I try to be consoling, but the hurt continues -- a hurt born of war, a cruel fact of My Phuong's young but divided life. It cuts deeply into our daughter's sense of herself, her feelings, her loyalties. The "aunt" is part of a very large foster family My Phuong once lived with in Vietnam; like My Phuong, she came to the United States to start a new life. But the similarities end there. A sharp generational gap, among other things, runs between the two refugees.

"Why did she do that?" My Phuong asks again.

Why, indeed? Perhaps the hurt must win sometimes, I think. Still, it never really triumphs. My Phuong has become good at surviving. Four years ago this spring, she arrived here so unfamiliarwith the ways of bright, shiny America that, at first, she applied roll-on deodorant to her face. However, that mistake was only a sliver of a larger, more serious picture: Experts say resettled Amerasians from Vietnam -- the children of American fathers and Vietnamese mothers -- can have difficult adjustment problems because their split identities have mixed so long with hardship and neglect.

Yet so far My Phuong has defied the experts, overcome the odds. This week she will graduate, a top student at T.C. Williams High School. Next will come college, then some ambitious plans. "I want to go back to visit Vietnam and see if I can help anybody," she recently wrote in applying for college aid. "I am ninety percent sure I will work either in business or communications after that."

For My Phuong, getting to this point has involved profound changes, some related to being a refugee; others, a teenager; and, still others, an Amerasian. Many young people like her would be discouraged. But My Phuong is confident that she can map out her future, and she even laughs now about her first awkward days in this country. These are good signs, antidotes for tearful Sundays. Ultimately, the hurt of war does not triumph over her -- it just reminds one of what My Phuong has been up against, and what she is defeating.

Ipicture her boarding the airliner at Tonsonhut Airport in Ho Chi Minh City. It is May 1986. "I cannot describe how frightened I was," she remembers. "I looked around, saying goodbye to all that I knew." What My Phuong knew was not very much. Given away as an infant, she lived in foster homes in Vietnam, ending up with "Grandfather" Sau, an elderly man who brought her into a family of a dozen children. Sau treated My Phuong well -- he even spoiled her -- but My Phuong's light skin, her "American-ness," set her apart in Vietnamese society. "I never really fit in," she says. "Because I was Amerasian, I was not accepted."

After Sau died in 1982, his older children contacted Vietnamese emigration authorities and presented My Phuong as a young half-sister. Perhaps they had learned that Amerasians are priority emigration cases in Vietnam and hoped they could leave the war-ravaged country with her. But officials determined that My Phuong had no blood relatives, and when she finally left for the United States she was alone, on her own.

My Phuong was just 14 the day she landed in New York. She felt dazed: "It was like being a person who is blind for many years, and now, suddenly, that person's eyes are open in a bright light." On one hand, she was fortunate; she had been sponsored by the United States Catholic Conference and immediately found a place in the social services system as a ward of the Richmond diocese. On the other hand, she was far, far behind. My Phuong knew no English and had no money. Her education had slipped; the Vietnamese authorities had stopped her schooling for two years, from the time she got permission to leave to the day she departed. And her "skills" -- hawking motorbike parts on Ho Chi Minh City streets -- hardly held promise for the U.S. job market. In her young eyes, the future looked frighteningly uncertain.

Gradually, however, a new life took hold. Her birth name, which means "Vietnamese American," seemed hard for people to pronounce, spell or remember -- so somehow she acquired the name Rachel at school. Her language and dress started to change and streets began to look familiar. And My Phuong met the phone, the chosen utility for millions of American teenagers.

Nothing closed the gaps in her heart, however. She had hoped to find acceptance at last in the United States; instead, she passed through foster homes just as she had in Vietnam. One family had to move, leaving her behind. In a second home, there were insurmountable problems. But she never abandoned her search for a family she could call her own. Last December, at a welcoming dinner when she moved into our house, My Phuong passed out wallet-sized copies of her senior picture.

"Dear Dad," she wrote on the back of mine, "I am very nervous and scared . . . plus very happy . . . . I hope it will work out for us . . . ."

The way My Phuong studied for a school test one night sticks in my mind as an example of the strengths she somehow summons. For hours that evening, she played recorded lessons on a tape deck that she normally loads with Vietnamese and American rock songs. On and off, went the tape, on and off, as My Phuong carefully listened, wrote out words she did not understand, then asked me their meanings.

She was not doing her English homework, though; the lessons were part of a computer course. My Phuong was simply making sure she could understand the exam questions. The real focus of the test -- how to operate a computer -- had to wait.

"You should not have to go through this," I said, doubting that many other students bore such a double burden. I was certain My Phuong would quit. Yet she kept working the tape -- rewinding, fast-forwarding, eagerly pushing the control buttons -- until finally, of course, she had mastered both the English and the computerese.

In the few months she has been with us, the frustrations of that night have been repeated in much of what has happened this side of her divided life. Nothing quite goes the way it should, and My Phuong has to mount a great and steady effort just to get through, to do the most ordinary things. America must look and feel so big to her; it must seem to burst with difficult but unavoidable challenges.

"Do you have a backpack?" my wife and I inquired one day shortly after her arrival when My Phuong came home from school exhausted from carrying an armful of textbooks half her weight. "Do you want a pillow to sit on," I asked, seeing her 90-pound frame barely poke above the steering wheel of our car at the start of a driving lesson. And the endless forms -- the college admission papers, the summer job applications -- all the bureaucratic rites of passage teenagers face -- how quickly they bring My Phuong's vague past to the surface. "Mother's name? Father's?" the forms demand.

How does one say the war stole the answers?

Back in Vietnam, "Grandfather" Sau tried to fill in some of the holes in her background. He assigned her a birth date, and clearly she is a teenager. However, my wife and I wonder exactly how close Sau came to reality. At times, My Phuong playfully hides her tiny body behind furniture, then pops out shrieking "Hi Dad!" or "The Fog is coming!" -- a warning cry from a horror video we watched together. As My Phuong dashes off, alive with laughter, we are sure that she is younger than 18. But then, she will do something difficult and responsible, like ending a relationship with a well-meaning but "too serious" boyfriend because she does not want to mislead his heart; at those times, My Phuong appears older.

And when the hurt of war bears down like it did the Sunday My Phuong became upset by her aunt, she looks much, much older, older than us, older than the hills, as if she never has been just a kid. The unknowns; the unresolved hurt; the pressures of being on her own, alone and adrift; the complications of belonging to two very different peoples, countries and cultures separated by years of bitterness -- it never rests, and it eats up young, innocent lives so easily.

And the pressures continue. In her desk, mixed in with school papers and a driver's permit, My Phuong keeps letters from another foster-relative, a desperate uncle still stuck in Vietnam. For years, he has been trying to leave legally for the United States, and he cannot understand why his emigration application remains unapproved. He wants My Phuong to determine the problem and to send him money -- as she has done before.

But the uncle is not the only needy one. On another Sunday, I enter the act. "Where is My Phuong?" I ask anxiously; she disappeared hours ago. My wife reports that she is at her girlfriend Chau's enjoying a dinner of banh xeo, a favorite shrimp-stuffed pancake.

Suddenly, I turn blind about our daughter, her needs for cross-cultural companionship and native food, her brave accomplishments. I just want her home, spending time with us as a family. My Phuong will go to college near home this fall and can remain with us indefinitely, but we all know that she must and will become increasingly independent. I go to bed uneasy, thinking that I have grown so attached to her, that I have become unreasonable and possessive.

Early the next morning, we notice that My Phuong has already sensed that her long absence the previous afternoon had caused some concern, and she has gone about the business of survival. My wife comes back into the bedroom with something she finds by the door -- an apologetic note from ever earnest My Phuong.

"I am very sorry," she writes. "I hope both of you forgive me. I promise I will never upset you again."

Joseph Cerquone is a free-lance writer in Alexandria.