Stocks slip on China-US tensions; oil resumes its slideNEW YORK (AP) - Stocks around the world are falling Monday morning, and U.S. indexes gave up modest early gains and turned lower, hurt by sharp drops for energy and financial companies. The British pound is dropping after the U.K. prime minister postponed a vote on its departure from the European Union, and oil has resumed its sharp slide. KEEPING SCORE: The S&P 500 index lost 47 points, or 1.8 percent, to 2,585, as of 11 a.m. Eastern time. The Dow Jones industrial average fell 435 points, or 1.8 percent, to 23,904, and the Nasdaq composite dropped 73, or 1.1 percent, to 6,894. U.S. indexes have been lurching up and down since October, mostly down, and the S&P 500 plunged 4.