Alessandro Rebaudengo, a 17-year-old student at Montgomery College in Takoma Park, returned to his native Venezuela two weeks before the end of his first semester and canceled plans to attend summer school.

"It's all because of the oil prices," Rebaudengo explained. When he arrived here last December, the dollar sold for 4.3 bolivars and his parents could send him as much money as he needed.

But now, because of falling oil prices and a foreign currency shortage back home, the bolivar of his oil-producing nation has been devalued to a rate of eight to the dollar. That means these students' families must now send them nearly twice as much money at a time when their own incomes have shriveled because of their country's economic problems.

And while Venezuela permits Rebaudengo and other students to receive $490 a month calculated at the old exchange rate, the students say they must submit extensive documentation to the consulate in Baltimore to receive that money and have been waiting several months for it.

Venezuelans are the latest group of foreign students in the United States whose governments have imposed foreign currency restrictions that are making it difficult for them to finance their studies.

The problem has most recently affected students from oil-producing countries, who represent a third of the 326,000 foreign students in the United States, according to the Institute for International Education. Many of these countries have been imposing foreign currency restrictions to counteract the recent drop in oil prices.

About 8,900 foreign students study in Maryland schools, according to the U.S. Immigration and Naturalization Service, and most are from developing countries.

Their student visas prohibit them from working off campus, and exceptions are granted only for students facing "unforeseen economic circumstances," INS spokesman Russell D. Manchester said.

That definition does not necessarily include a currency devaluation, he said.

Iranian students face not only long waits for their money but must meet Iranian government requirements to get their funds: a 2.5 grade point average and the study of such "required" courses as medicine and engineering, according to one of the 208 Iranians at the University of Maryland, a PhD student in political science who asked not to be named.

"The Islamic government feels that the Koran is the only true teacher of philosophy, politics, anthropology, et cetera," the student said. "So we are only allowed to study subjects that they feel are important to the revolution."

He and his fiance, who is studying for a master's degree in cartography, are able to receive money because they began their studies before the fall of the shah in 1979. But, he said, many of the 28,000 Iranian students who remained in the United States since then cannot receive money and have had to seek illegal employment to finance their studies.

Iranians were once the United States' largest group of foreign students, with 51,000. They left en masse after the revolution, underscoring the vulnerability of foreign student enrollment to global political and economic factors, area university officials said.

The combined effects of low oil prices and high inflation rates in such countries as Argentina and Brazil could cause a further drop in foreign enrollment, which foreign student advisers say could affect area universities both culturally and financially as well as cause hardship for the students.

Nigerians, who say they have never have been able to collect money easily, are coping with foreign currency restrictions imposed in January by their economically troubled government.

"This is affecting them in two ways," University of Maryland foreign student adviser Valerie Woolston said. "First, the students cannot get as much money from home and are having to wait longer for that money. And also, many of the scholarships they were granted are simply being canceled by the state governments in Nigeria."

Woolston, who has been at the university five years, said about 10 of the college's 41 Nigerian students dropped out of school between the fall and spring semesters and many cannot raise even enough money for the flight home.

"It becomes a terrible, vicious cycle," she said. "First, these students can't get money out of their countries and then they cannot enroll in school. If they can't enroll in school, they can't get their student visas."

Woolston said the Nigerians and Iranians can apply for work permits at INS. But many are afraid to apply because if they are turned down, they have revealed their situation to the INS, which does not look kindly at foreign students working illegally.

Woolston is vice president of the Washington-based National Association for Foreign Student Affairs, an organization of foreign student advisers and administrators funded by the U.S. Information Agency and the Agency for International Development. The association has been requesting that foreign students' problems be addressed on a diplomatic level in its meetings with State Department officials.

The association's information director, Georgia Stewart, said she sees the INS no-work rule and recent tightening of visa requirements as inconsistencies in U.S. foreign policy.

"The State Department, through AID and the Caribbean Basin program, is handing out scholarships and inviting them to come here," she said. But the INS is making it difficult for them to stay here, she added.

Many foreign students interviewed, particularly the large numbers who come from India, said they normally cope with the financial uncertainty by either smuggling money here or working illegally.

One, an l8 year-old computer science student at Montgomery College, said he is sponsored by an uncle who lives here in Silver Spring. The uncle, he said, is handed money by his parents in India during yearly vacations there.

Dale Gough, international admissions counselor at Maryland, said that in some cases these students, often from affluent families, are simply unwilling to subsist on the small amounts of money their countries allow them to exchange.

Most university officials interviewed said the dramatic exodus of Iranians studying in this county after the revolution has taught them not to depend heavily on revenue from large groups of foreign students. Because most of the students try to stay in school long enough to earn their degrees, their financing problems have not yet been translated into enrollment decreases.

But the area's English-language schools, many of which prepare foreign students for university study, are experiencing dramatic enrollment decreases.

Temple School in Silver Spring, a business college that teaches English as a second language, once had 27 Venezuelan students--40 percent of the enrollees in their language program. Said program director Jackie Fliegner: "They all went home for the Christmas holidays, and only three returned this year."