What was going on when I was born?

The Reagan Administration has told allied governments in recent days that it expects Soviet-American relations to enter a new phase, marked less by polemics and more by concrete discussions of arms control and other issues. Conversations with Administration officials and senior diplomats indicate that Secretary of State Alexander M. Haig Jr. and others have made an effort to convey the view that the two superpowers, despite their sharp differences, have been holding a serious dialogue that is expected to intensify soon. But at the same time, the Administration has told diplomats and journalists not to expect rapid progress in the Soviet-American talks on medium-range nuclear forces that are to begin Nov. 30 in Geneva. Those negotiations have received extensive publicity in the last week as a result of President Reagan's offer to forgo deployment of new American missiles in Europe if the Russians dismantle those they have already deployed. The two sides seem far apart even on the basic question of which weapons systems should be included in the initial negotiations.

HARTFORD THE most durable issue at the State Capitol this year has been the unincorporated business tax. Just when it appeared that the General Assembly was on the verge of repealing the tax that it had enacted at the regular legislative session last spring, Governor O'Neill called for changes in the levy to bring in more money to help close a deficit in the current fiscal year ending June 30. The Governor's proposal put the tax on unincorporated business at center stage once again as the legislators convened last Thursday for their special session to grapple with the state's fiscal problems. The history of the tax provides an example of the financial and political problems that arise as Connecticut and its elected officials struggle to find new sources of revenue to continue state programs during a time of high inflation and reduced fiscal aid from the Federal Government.

COLD SPRING HARBOR FROM the four-lane section of Route 25A here, opposite the children gawking into the tanks of the state fish hatchery, there is little to reveal the presence of the Cold Spring Harbor Laboratory except a very small sign and a curiously large number of parked cars. Inside, on the main driveway, the Colonial-style wood and stone buildings still give little hint that this is a world-famous center of research on the frontier of modern molecular biology. In a virtual village of their own, 80 scientists are single-mindedly pursuing the keys to DNA and the mechanisms of cancer and other cells, among other work. Their research - which recently produced what may be a breakthrough in understanding cancer - is believed to have such tremendous industrial potential that commercial interests could change their way of operating. How and where such research could be utilized by business is not clear to some of the scientists at the laboratory, but for some companies even the possibility of looking at the preliminary results of the research could be enough of an incentive to start thinking along commercial lines.

THE COLLECTED POEMS By Sylvia Plath. Edited by Ted Hughes. 351 pp. New York: Harper & Row. Cloth, $17.50. Paper, $7.95. The facts of the case are easily reported. Sylvia Plath was born on Oct. 27, 1932, daughter of Otto and Aurelia Plath. Her father taught German at Boston University and in 1934 published a study of bees. He died on Nov. 2, 1940. Sylvia had a scholarship to Smith College, where she won the prizes, including a Fulbright to Cambridge University. In 1956 she married the poet Ted Hughes; their first child, Frieda, was born on April 1, 1960, their second, Nicholas, on Jan. 17, 1962. In October 1962 the marriage fell apart, and they separated. A girl who lived mostly and terribly on her nerves, Sylvia made several attempts to kill herself, the first apparently in 1953. She died by her own hand on Feb. 11, 1963. Plath's first important book, ''The Colossus,'' was published in 1960, and her novel, ''The Bell Jar,'' appeared a few weeks before she died. But most of her work was published after her death: ''Ariel'' (1965), ''Three Women'' (1968), ''Crossing the Water'' (1971), ''Winter Trees'' (the same year) and a book of stories, ''Johnny Panic and the Bible of Dreams'' (1977). To a few readers Plath was already a legend before her death, but the publication of ''Ariel'' made the legend common if not universal property.

ALTHOUGH Government and industry analysts say it is doubtful that any gas or oil would be found within 50 miles of the shores of Long Island, James G. Watt, the Secretary of the Interior, has raised the possibility that drilling rigs could appear offshore anywhere from Rockaway Beach to Montauk Point. Exploratory drilling for gas and oil as close as three miles would be permitted in an offshore lease sale that he recently proposed as part of the Reagan Administration's policy to spur the nation's search for new energy sources. ''He's legally saying that anyone who's interested in bidding can seek a lease for drilling for oil three miles out,'' said George Wilde, president of the Friends of Long Island, which, like other environmental groups, has reacted angrily to the proposed sale. Lee E. Koppelman, executive director of the Long Island Regional Planning Board, said: ''Should the law ever permit an oil rig within three to five miles of the shore, and there was an oil spill, there is no doubt that it would do damage to Long Island.'' He described Mr. Watt's oil-leasing policy as ''gratuitous'' and ''a slap in the face to local government and economic interests.'' ''Watt is displaying an arrogance and insensitivity that's creating an adversary situation, which could be avoided with a little common sense,'' Mr. Koppelman said.

When Jose Carreras, the young Spanish tenor, sang in Franco Zeffirelli's ''La Boheme'' with the La Scala opera company in Washington five years ago, he was Rodolfo. He had the soft, sensitive, boyish-looking face one always felt Puccini's young poet should have. He moved with hesitance at times, as if he were unsure of what to do next. He held Mimi's hand as if he were truly afraid he might crush it, and when he sang ''Che gelida manina'' to her, he seemed to be expressing the sudden discovery of a fragile truth. His singing was natural, unaffected, disarmingly lyrical. His voice had a lustrous sheen in the upper register, with flashes of fire that set it somehow, indefinably, apart. One sensed immediately what a rarity he was. A repertory conductor for a small European house once described the Carreras phenomenon in these terms: ''He's young, he's handsome, he's intelligent, he can sing and he's a tenor!'' It has been three years since New York has seen Mr. Carreras in an operatic production. This season he returns to the Metropolitan Opera for four performances of ''Tosca'' and ten in a new production by Mr. Zeffirelli of ''La Boheme,'' which opens Dec. 14. Also in December, he sings a solo recital at Carnegie Hall and a joint concert with Montserrat Caballe in Fisher Hall.

BONN NOW the ''peace war'' begins in earnest. After President Reagan moved his ''program for preserving peace in Europe'' into place last week, Leonid I. Brezhnev arrives in Bonn tonight and is expected to fire a return salvo of the new soft and conciliatory vocabulary (for the Reagan team, at least) in a battle that will run at least into 1984. Roughly, the issue is the North Atlantic Treaty Organization's plan to install new middle-range nuclear weapons in Europe as a response to Soviet Euro-missiles. More significantly, however, the question involves the future of the Atlantic alliance, Mr. Brezhnev's attempts to break it down by exploiting the pacifist and neutralist trends in member countries and the Reagan Administration's new awareness that the alliance will hold together only to the extent that Europe is convinced that Washington is protecting its peace rather than preparing its war.

There was more than one game going on here this afternoon before a sellout crowd of 60,234 at Husky Stadium. One was on the field, where Washington was on its way to defeating its crossstate rival, Washington State, 23-10, and earning a second consecutive trip to the Rose Bowl. The other game was in the stands, where hundreds, possibly thousands, of portable radios were tuned into that other big Pacific-10 Conference game - Southern California against U.C.L.A. At times - like when swells of cheers arose from the stands at odd times during the game on the field - it was hard to determine which contest was the more important of the two. Washington State entered the game as the surprising leader of the conference with an 8-1-1 record. If the Cougars won here, they would go to the Rose Bowl on New Year's Day, their first bowl appearance in 51 years.

Buying Oil Companies Mergers and acquisitions have always been common in the oil industry, but oil companies are generally the purchasers, not the targets. Thus U.S. Steel's $6.3 billion offer for Marathon Oil is a striking departure, and there could be others like it. And with oil prices expected to fall in real terms next year, some analysts say oil company assets and stock prices are likely to continue falling, setting the stage for more takeovers. Although a 40 percent decline in the value of oil company shares since last November suggests that the markets have already discounted falling oil prices, further declines next year are likely to hit smaller oil companies particularly hard, experts say.

''IT's not that I have this grand mission to help others, but I know I have something to give,'' said Kay M. Herbert of Port Washington, a 44-year-old bookkeeper for a real-estate management firm. ''In my lifetime a lot of things have happened to me that can benefit other people, and I think the best thing you can do is share this experience and knowledge with others.'' The feelings articulated by Mrs. Herbert are representative of those expressed by an increasing number of Long Islanders who, in addition to holding full-time jobs, are applying to work as unpaid volunteers for the many Long Island organizations that need their services. ''Our applications from full-time workers are up by 50 percent over last year, and they're still rising steadily,'' said Dorothy Burnham, director of the Suffolk County Voluntary Action Center. ''Now at least half of our requests are coming in from people who work.''

HEMPSTEAD, L.I. H E debated whether he could play, but Richard Todd finally decided: ''I want to be in there. I feel like I've gotten us this far.'' And so, dramatically on Saturday, he donned an outfit with a flak jacket and a microphone, suited up, and led the New York Jets through their final workout before Sunday's showdown for first place against the Miami Dolphins. It marked the first time since last Sunday, after he cracked a rib playing against the Patriots, that the Jets' quarterback had directed the team, and apparently put to rest doubts that he would perform. Still, Coach Walt Michaels said after the workout: ''I can't know until the pre-game warm-up. But if he throws the ball like he did today ....'' If so, Todd starts and Pat Ryan, his longtime back-up, would be available to step in on his heavily taped sprained right ankle.

FEW restaurants in the county offer fine classic French cuisine, and even the best of these occasionally falter in a world where all is flux. Reputations of restaurants follow paths that swoop and soar according to changes in ownership, kitchen personnel, dining room staff and, not insignificantly, the economy. It is gratifying then to see Auberge Argenteuil in Hartsdale thrive under the new sole ownership of Henri and M'el Eudes. The menu streamlined, dining room staff efficient, dining rooms refurbished, thoroughly professional kitchen orchestrated by its longtime chef de cuisine, Francois Kerohas, together with Mrs. Eudes's gracious warmth and Mr. Eudes's felicitous attentiveness as he suggests special dishes and appropriate wines from his cellar - that old magic is there again. Right now Auberge Argenteuil is one of our favorite dining places this side of the Atlantic. Among the many fine dishes the kitchen sends forth, soups proved exceptional. Once poorly balanced and overly salted, the harmonious concoctions provided an auspicious beginning to the meal, whether one chose lobster bisque, a jot too intense with saffron but nevertheless intoxicatingly rich and heavy with magenta crustaceans, or one of the daily soups: glowing vegetables in a cheerful, transparent broth; St.-Germain, the soothing pureed pea soup adrift with homemade croutons; subtle fish soup edged with Gruyere shavings; pungent watercress soup cream-smoothed.