What was going on when I was born?

The Metropolitan Transportation Authority may have to increase New York City's bus and subway fares more than it had expected because of the refusal of two oil companies to pay the state's gross-receipts tax, state officials said today. The authority, already projecting a deficit of $150 million for next year, faces an additional loss of up to $100 million this year because of the actions by the companies, the officials said. The chairman of the Metropolitan Transportation Authority, Richard Ravitch, said that if the state did not make up the difference by June 30, the end of the Transit Authority's fiscal year, ''then obviously we're going to have to increase the fare even more, borrow the money or something.'' Early Steps on Fare Increase The authority has already taken the first steps toward a fare increase of 10 to 15 cents on July 1. The companies contend that the law is unconstitutional because it forbids them to pass along the cost of the tax to consumers. The issue is being fought in court.

Two-hour strikes broke out in at least four northern cities today, and the Solidarity union declared a nationwide strike alert in an angry response to last night's police attack on union activists in Bydgoszcz. A resolution adopted by the leadership of the independent union movement at 4 A.M. announced the suspension of all talks with the authorities and called upon all union chapters, representing some 10 million Polish workers, to be ready to strike by Monday. A definite date for a strike was not set, however, and it was clear the union did not hold top Government officials directly responsible for the police action and was giving them two days to try to calm the situation. 3 Badly Injured in Raid In the incident at Bydgoszcz, about 200 riot policemen beat two dozen members of the union and an affiliated farmers' group, Rural Solidarity, while evicting them from the hall of the provincial assembly. Three people were seriously injured, including a leader of Solidarity's national commission, Jan Rulewski.

An angry Jean S. Harris was sentenced today to a minimum of 15 years to life in prison for the murder a year ago of Dr. Herman Tarnower. Judge Russell R. Leggett of County Court said he wished ''the events of March 10 had never taken place.'' Mrs. Harris, who had been the 69-year-old cardiologist's companion and lover for 15 years, was defiant. ''I did not murder Dr. Tarnower; I loved him very much,'' she said, trembling as she stood before the judge. ''No one in the world feels his loss more than I do. I'm not guilty.'' Her comments drew applause in the packed courtroom after a long day that saw Joel Aurnou, her lawyer, challenge the jury's re-enactment of the shooting in the doctor's bedroom as improper. Judge Leggett rejected the contention, saying the jurors ''did what they were asked to do, trying to determine what they could believe and could not believe.''

The Exxon Corporation announced yesterday that it had abandoned the electronic control for electric motors that it introduced as an energy-saving breakthrough two years ago. The company had invoked the promise of development of the control as justification for its controversial $1.2 billion acquisition of the Reliance Electric Company. Exxon said that its development work had now been focused on an alternative design because it would cost too much to make the original one reliable enough for industrial applications. Yesterday's disclosure prompted criticism of Exxon, which the company disputed, and renewed concern about the rising influence of the large oil companies.

President Reagan's top aides have evicted the informal advisers known as his ''kitchen cabinet'' from the offices they used in the Executive Office Building. It was the second move to limit the activities of the group of wealthy friends of the President who have attempted to influence the Administration's appointments and policies. The first move came yesterday, when, at the urging of the White House, Mr. Reagan's friends disbanded the Coalition for a New Beginning, which had raised $800,000 to finance a lobbying campaign for the President's economic program. The dismantling of the coalition, which involved many members of the kitchen cabinet and was formed last month with White House approval, was advocated by Mr. Reagan's chief of staff, James A. Baker 3d. The White House said today that Edwin Meese 3d, the White House counselor, had taken the lead in ordering kitchen cabinet leaders, including William A. Wilson and Joseph Coors, not to use the office from which they had conducted checks on Presidential appointees' acceptability to conservatives.

The Defense Department said tonight that 18 of the 54 United States military advisers sent to El Salvador would return to this country by July after completing their assigned training missions. A Pentagon spokesman insisted, however, that the return of the advisers involved ''no significant changes in the overall plan.'' The spokesman, Lieut. Col. Erik Opsahl, stressed that the advisers were not being ''withdrawn.'' As explained by the Pentagon spokeman, the advisers were sent to El Salvador for specific tasks, such as showing Salvadoran military personnel how to train their own troops in such areas as helicopter operation and maintenance and in using new combat equipment. Among the 54 advisers are 15 members of the Army's Special Forces, known as Green Berets, who are specialists in counterinsurgency training.

''Now repeat after me,'' Senator Jesse Helms, Republican of North Carolina, solemnly told the gathering of more than 500 farmers and warehousemen today. ''There is no tobacco subsidy.'' Almost with one voice, delegates to the 34th annual meeting of Tobacco Associates, a Southern growers' lobby with a special interest in promoting exports, responded to the increasingly powerful chairman of the Senate Agriculture Committee: ''There is no tobacco subsidy.'' The packed meeting in the Sheraton Crabtree Hotel here was, in almost equal parts, a celebration of North Carolina's political power in Washington and a united stand by one of the nation's better-known interest groups against possible budget cuts. . Action by Budget Committee Late Wednesday evening the Senate Budget Committee rejected, by a vote of 9 to 7, a proposal to eliminate tobacco price supports totaling $63 million. The proposal by Senator Howard M. Metzenbaum, Democrat of Ohio, was backed by four Republicans and three Democrats. But the committee recommendation need not be followed by the Agriculture Committee, which was instructed to find $4.3 billion to cut from the Federal budget wherever it could.

West Germany announced today that it had exchanged a group of prisoners with East Germany. Sources close to the Government said the exchange took place yesterday. A spokesman, Kurt Becker, said it was done ''for humanitarian reasons,'' but he did not elaborate nor say how many were involved.

Japan is expected to explore United States attitudes on two key issues - exports of Japanese autos to the United States and Japan's contribution to security in the Far East - when Foreign Minister Masayoshi Ito visits Washington next week. Mr. Ito leaves here tomorrow and his schedule includes a courtesy call on President Reagan Tuesday and sessions with Secretary of State Alexander M. Haig Jr., Defense Secretary Caspar W. Weinberger and Bill Brock, the chief trade representative. Mr. Ito, 67 years old, is not expected to negotiate. He told foreign reporters here yesterday that his chief task was to sound out American positions.

The Cuban Government said last night that Portugal was not justified in ordering the Cuban Ambassdor in Lisbon, Manuel Estevez Perez, out of the country last Wednesday. The expulsion came amid a growing dispute over Cuba's accusation that a Portuguese charge d'affaires here, Francisco de Sales Mascarenhas, had been in touch with the Central Intelligence Agency and had helped plan last month's seizure of the Ecuadorean Embassy in Havana.

Shimon Peres, the Labor Party's candidate for Prime Minister, confirmed today that he met this week with Arab leaders, but would not say with whom. He said he had obtained express approval from Prime Minister Menachem Begin. The Israeli state radio and television reported that Mr. Peres, accompanied by Israeli security agents, flew to Morocco to meet with King Hassan II and also that he had spoken in London with a brother of King Hussein of Jordan. The Moroccan Information Minister, Abdel Wahed Belkaziz, was reported from Marrakesh to have denied the report. Mr. Peres would say only: ''I have nothing to add to this denial.''

Rejecting the criticisms and warnings of two opposition political parties, the voters of Canada's most populous province have re-elected the conservative government of Premier William Davis, giving him a strong mandate to confront persistent problems. According to final returns in yesterday's provincial election here in Ontario, Mr. Davis's Progressive Conservative Party captured 70 of the legislature's 125 seats, an increase of 12. The Liberals again won 34 seats, while the socialist New Democratic Party suffered a loss of 12 seats, down to 21 members. It was an impressive victory for the 51-year-old Mr. Davis, whose party has won every province-wide election in Ontario since before the allies landed in France in 1944. Mr. Davis, who managed only minority victories in the last two elections, has led his party since 1971.