Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
Commodity stocks pared early gains and weighed on the big board, as oil prices reversed early increase and dipped below 70 U.S. dollars a barrel on the New York Mercantile Exchange.
Tech stocks rallied as Apple shares climbed with the maker of the iPhone releasing an updated version on Friday. And Microsoft Corp. rallied 2.4 percent, the most in a month, after Goldman Sachs Group Inc. added the world's biggest software maker to its "conviction buy list."
Major health care companies were also boosted as the Obama administration's plans to overhaul the nation's health care system make their way through Congress.
Trading volume was heavy on Friday because of the occurrence in the day of a quarterly "quadruple witching," which marks the simultaneous expiration of a number of different options contracts.
The Dow Jones dipped 15.87, or 0.19 percent, to 8,539.73. Broader indexes inched up. The Standard & Poor's 500 index rose 2.86, or 0.31 percent, to 921.23, and the Nasdaq added 19.75, or 1.09 percent, to 1,827.47.