Steven Mnuchin speaks during a hearing of the Senate Finance Committee in Washington D.C., the United States, Jan. 19, 2017. Steven Mnuchin, U.S. President-elect Donald Trump's nominee for treasury secretary, said on Thursday that it was important to keep the U.S. dollar strong in the long term, walking back Trump's earlier comments on the U.S. currency. (Xinhua/Bao Dandan)