The U.S. economy expanded in the third quarter for the first time in more than a year thanks to a bounce back in consumer spending, but a weak labor market is expected to keep the recovery subdued.Gross domestic product rose by a higher-than-expected seasonally adjusted 3.5% annual rate July through September, the Commerce Department said Thursday in its first estimate of third-quarter GDP.Economists surveyed by Dow Jones Newswires had forecast 3.2% GDP growth during the summer. GDP is the broad measure of economic activity in the U.S.