U.S. stocks closed sharply lower, yesterday, as investors weighed the ongoing Greek debt crisis and a disappointing report showing that the US economy shrank in the first quarter. Economists are looking ahead to the June 5 release of the jobs report for May, after U.S. employers rebounded and created more jobs in April following a sharp slowdown in March.So the Dow Jones Industrial Average dropped 99 points, the Standard & Poor's 500 lost 12 points, and the Nasdaq Composite fell 24 points.The U.S. economy contracted in the first quarter as it buckled under the weight of unusually heavy snowfalls, a resurgent dollar and disruptions at West Coast ports, but activity already has rebounded modestly. The US government slashed its GDP estimate to show the economy shrinking at a 0.7 percent annual rate, instead of the 0.2 percent growth pace it had estimated last month. A larger trade deficit and a smaller accumulation of inventories by businesses than previously thought accounted for much of the downward revision. There was also a modest downward revision to consumer spending. With growth estimates for the second quarter currently around 2 percent, the US economy appears poised for its worst first-half performance since 2011.