September 3, 1986

''What our children need are lessons that explore unfamiliar possibilities, that play on their imaginative capacities while teaching core democratic values like respect for persons, property and truth.'' - Secretary of Education William J. Bennett. [ A1:5. ]

MARGUERITE MARGASON was unlike the other girls attending Blessed Sacrament parochial school in Seattle in the early 1950's and it went beyond the beret and sandals her mother insisted she wear. ''Here comes Fish Eggs,'' the girls would say at lunch. As they peeked under the corners of their peanut-butter sandwiches for reassurance that all was in order, Marguerite would unwrap a sandwich of salmon roe, tomato and freshly made mayonnaise. Today, Mrs. Margason is just as likely to lunch on pigskin and rose petal salad, a Thai dish she not only discovered in one of the many obscure cookbooks she has collected on her worldwide travels, but also took the trouble to cook and add to her repertory. That is the primary difference between Mrs. Margason and the vast majority of her culinary contemporaries. She knows no bounds.

In its recent efforts to ward off a raft of low-cost competitors in the personal computer market, the International Business Machines Corporation has slashed prices, tossed in free software and touted its tradition of reliability - all to little avail. So today the world's largest computer maker, struggling to recover from a surprising loss of market share, took a new tack. It introduced a significantly faster version of its PC XT - the first major change in its basic PC design since I.B.M. entered the personal computer business in 1981 - in hopes of bringing some of its largest corporate customers back into the fold. The $3,995 entry, called the PC XT Model 286, is built around the Intel 80286 microprocessor, the same chip that powers I.B.M.'s top-of-the-line PC AT.

The small plane that collided with a Mexican airliner in California Sunday was transmitting radar signals that were recorded by the traffic control computer, the director of the Government inquiry said yesterday. John Lauber, a member of the National Transportation Safety Board, said the signals would presumably have shown up on the controller's radar scope. But the small Piper PA-28's blip on the radar scope would not have shown its altitude, Mr. Lauber told a news conference in Los Angeles. Therefore, the controller could not have known that the craft and the airliner were at the same altitude and headed for a midair crash.

In a crackdown against under-age drinking, undercover investigators will begin spot checks of New York City's thousands of bars this week, state and local officials announced yesterday. ''We're putting the proprietors of bars on notice,'' Mayor Koch said. ''We're going to enforce the law as strictly as we know how.''

The United States said today that it would provide no new economic aid to Zimbabwe because of what it called that country's lack of ''diplomatic civility.'' The move, which will cost Zimbabwe $20 million that it might have received in the next aid budget and $13 million approved for the current year but not yet allocated, followed an episode on the Fourth of July. At an Independence Day celebration at the United States Embassy, a Zimbabwean Cabinet minister attacked the Reagan Administration for its refusal to impose economic sanctions on South Africa. His remarks prompted a walkout by former President Jimmy Carter and a senior American diplomat. Mugabe Bars Apology to U.S. Washington announced a few days later that it was suspending aid and would review its aid policy. Prime Minister Robert Mugabe said his Government would apologize to Mr. Carter because his administration had been a friend of Zimbabwe, but he said Zimbabwe would not apologize to the United States Government.

The State Department today rejected any attempt by Moscow to link the release of an imprisoned American correspondent with that of a Soviet physicist arrested on spy charges in New York 10 days ago. A department spokesman, Charles E. Redman, said that ''we can't rule out'' that Moscow was trying to ''influence'' the case of the physicist, Gennadi F. Zakharov, a United Nations employee, by arresting Nicholas S. Daniloff, a correspondent for U.S. News & World Report, in Moscow last Saturday. Mr. Daniloff has since spent four days in prison. Cases 'Completely Different' But Mr. Redman said ''the two cases are completely different in nature.''

In a move that would create the 24th-largest banking organization in the nation, SunTrust Banks Inc. of Atlanta yesterday reached an agreement to buy the Third National Corporation of Nashville. The combination, which has been approved by the boards of both banking companies and is expected to receive shareholder approval, would also create one of the nation's most profitable banking companies. Under the merger agreement, SunTrust will exchange 1.67 of its shares for each of Third National's 18.9 million shares. Based on SunTrust's closing price yesterday of $23.25, the offer is valued at about $734 million.

Some of the investors who for the last few years have sunk billions of dollars into stocks and bonds now seem to be catching the gold bug. Yesterday, they drove the prices of gold and platinum to their highest levels in years, and the competition from the metals markets was cited as a factor in the plunge of stock market prices that sent the Dow Jones industrial average down 27.98 points. Gold prices jumped more than $18, to $405.70, on the New York Commodity Exchange, the highest close in nearly three years and more than $60 higher than a month earlier. Platinum rose more than $38 an ounce, to $663.20. A month ago it was trading at slightly more than $468 an ounce. Silver has not been generating the excitement of the other two metals, but it was up 27.5 cents, to $5.42, yesterday on the Commodity Exchange.

Secretary of Education William J. Bennett called today for a ''major reform'' of curriculums in the nation's 80,000 elementary schools. In an 83-page report, the country's top education official charged that science was too often taught as a ''grab bag of esoteric facts and stunts'' and that social studies curriculums were ''full of ersatz social science'' at the expense of history, geography and other traditional topics. ''What our children need are lessons that explore unfamiliar possibilities, that play on their imaginative capacities while teaching core democratic values like respect for persons, property and truth,'' he said in the report, titled ''First Lessons: A Report on Elementary Education in America.'' Some Criticisms Voiced In the document, which was issued over his own signature, Mr. Bennett also criticized the teaching of reading, writing, mathematics, the arts and foreign languages in elementary schools.

DON'T blink when you pass schoolyards this fall. Little learners will be wearing little versions of styles first fashioned by the likes of Donna Karan and Azzedine Alaia. At all prices and for all ages, children's clothes are no longer clothes; they're fashions. And those fashions are mimicking adult styles. ''Just as the fashion communication gap between Paris and New York no longer exists,'' said Terry Melville, junior fashion director of Macy's, ''in the same way, there is no longer a gap between kids, older siblings and their parents.''

A church on the West Side of Manhattan is petitioning the United States Supreme Court to revoke its status as a landmark, arguing that the financial hardship of such a designation interferes with the church's religious liberty. Trustees of the church, the Church of St. Paul and St. Andrew, believe their appeal marks the first time that the First Amendment's protection for the free exercise of religion has been used to argue against being designated as a landmark. ''We see de-landmarking as a necessary step to avert financial ruination and the possible foreclosing of the congregation,'' said the Rev. Edward C. Horne, pastor of the church, a United Methodist congregation at the corner of 86th Street and West End Avenue. ''We do not believe that a governmental agency has the authority to put us or any other religious body in such a position.''