WASHINGTON D.C., June 21, 2016 (Xinhua) -- U.S. Federal Reserve chairwoman Janet Yellen adjusts her glasses as she testifies before the Senate Banking Committee on Capitol Hill in Washington D.C., the United States, on June 21, 2016. U.S. Federal Reserve chairwoman Janet Yellen on Tuesday reiterated the central bank's intention to raise interest rates, taking a cautious approach in view of an uncertain U.S. economy. (Xinhua/Yin Bogu)