What was going on when I was born?

The American Telephone and Telegraph Company said yesterday that it would cut long-distance telephone rates by $1.75 billion a year, or about 10 percent, on Jan. 1. The proposed reduction is the result of a decision by the Federal Communications Commission that would add flat monthly charges to each telephone bill at the same time as it decreases long-distance bills. The so-called access charges of $2 for residential telephone lines and $6 for business telephone lines will also take effect at the first of the year. Although A.T.& T. called the announced reduction the largest in history, industry analysts and consumer advocates were quick to note that the reduced long-distance charges on the whole would not offset the increased charges from the flat monthly access charges, which are expected to total $3.5 billion in 1984.

To Americans, Canada is towering pine trees, majestic mountains and stalwart Mounties. At least that's the way Canadian beer makers see it, and they say it all adds up to big beer sales. ''Let's face it, people drink images,'' says H. Hollis Brace, president of Molson Breweries International. If so, Molson's image is certainly the strongest of the Canadian products. And with a flurry of award-winning radio ads and its first television campaign now in the works, that image seems likely to grow even stronger.

International Moscow sponsors and supplies the growing role of Syria in the battle for control of Lebanon, according to both President Reagan and Secretary of State George P. Shultz. They made the charge as both houses of Congress held hearings on a compromise formula that would authorize the continued presence of 1,200 American marines in Lebanon for 18 more months. (Page A1, Column 6.) Lebanon's leader visited the beleaguered Army garrison in Suk al Gharb as the stronghold came under another daylong tank and artillery attack from Syrian-backed Druse and Palestinian forces. The Beirut radio broke into a news report to announce that President Amin Gemayel had toured frontline positions. American warships fired salvos for the third successive day. (A11:1.)

Carroll Shelby, the one-time racing driver turned auto designer, put his cowboy boots up on the desk at the Chrysler Shelby Performance Center here and analyzed what went wrong for the American auto industry in California. ''People in Detroit think they're all a bunch of kooks out here,'' he said. ''But what the average Joe in California is looking for is practical transportation. Detroit was still trying to sell big boats that got eight miles per gallon when the imports came in here with well-built, well-finished cars that got 30 miles to the gallon. And then they were surprised at what happened.''

Because of an editing error, an article about the former basketball player Rick Kuhn in Sports Pages on Tuesday incorrectly attributed the statement that his cooperation with the authorities had led to the indictment of another former player, Ernie Cobb. The statement was made by the prosecutor, Edward McDonald.

An article and photo caption yesterday incorrectly identified a Chicago church that offers sanctuary to Central American refugees. It is the Wellington Avenue United Church of Christ.

''Maybe all those delegates should have six months in the United Nations meeting in Moscow and then six months in New York, and it would give them an opportunity to see two ways of life.

THERE was a time when neighbors dropped in to borrow a cup of sugar or to offer advice on backyard planting, but the home computer has created a new kind of neighborliness. Nowadays, the computer owner from next door drops in to borrow the little cartridges or disks that make computers do everything from play games to balance checkbooks, or for an advisory session on computerese. Last week in Watchung, N.J., John Andrews brought home a new printer for his Apple II personal computer. The three thick instruction manuals were filled with baffling jargon, so he called Richard Tillbrook, his next-door neighbor on Ellisen Road. Mr. Tillbrook, who has three personal computers in his basement, came right over. After an hour of fiddling with circuit boards and cables, he pronounced Mr. Andrews's printer ready for action. ''I've been doing this for years,'' he said. ''People I've never met come by and ask for help if they can't figure something out.''

Many years hence, Sir Harold Acton hopes, New York University will open a new center that it will have inherited from him far from Washington Square. It will comprise five splendid Renaissance or Baroque villas and a great, formal Tuscan garden mixing greenery with statuary. Between them there will be olive groves and vineyards on slopes that offer splendid panoramas of the domes and steeples of Florence below. For the time being Sir Harold, a sprightly man of 79 years, lives in the main villa, La Pietra, at the northern edge of the Tuscan capital, and looks and acts as though the university will have to wait for a long time to take possession of the property he has bequeathed to it. Assembled by Father Sir Harold, who described himself fittingly in the titles of his two volumes, ''Memoirs of an Aesthete'' and ''More Memoirs of an Aesthete,'' intends to spend many more years preserving, restoring and displaying the splendors of the estate, art collection and library assembled by his father, Arthur Mario Acton.

Under this heading, The Times amplifies articles or rectifies what the editors consider significant lapses of fairness, balance or perspective. Corrections, also on this page, continue to deal with factual errors.

Riverside Park, the slender strip of greensward that runs along the Henry Hudson Parkway by the banks of the Hudson River, is entering its second century, and a major restoration has begun. Work is starting on the promenade that goes from 101st to 110th Street. Once a formal, terraced area with large shady trees, it is now a cracking pavement surrounded by sick-looking grass and the skeletons of benches. With $910,000 from the city's capital budget, concrete borders will be refurbished, graffiti will be removed from parapet walls, new benches will be installed and missing trees will be replaced.

Security forces clashed Wednesday night with thousands of anti-Government demonstrators who tried to march on the presidential palace, and officials said at least seven people were killed and more than 150 wounded. Mr. Marcos, in an angry speech on national television at noon today, blamed the outbreak on ''a few hardcore radicals manipulating and exploiting a peaceful rally for their own purposes'' and warned that his Government would meet further violence with armed force. He added, ''I hold the opposition leaders responsible'' for last night's outbreak. Mr. Marcos said he was conferring with police and military commanders on plans for re-arming units assigned to political demonstrations, who had been ordered previously to carry out their duties without weapons and to exercise ''extreme tolerance.''