BEIJING (AP) — China’s central bank is trying to restrain the surging exchange rate of its currency, temporarily backtracking in efforts to make the tightly controlled yuan more flexible and market-oriented. Commercial lenders have been ordered to hold more of their foreign currency as reserves in the central bank to limit sales after the yuan hit a four-year high against the U.S dollar. The People’s Bank of China is trying to deter speculators after the yuan rose by about 12% against the dollar since May. Beijing said in 2015 it planned to make the yuan “freely tradable” by last year. But it has kept controls in place due to concern about the flow of money into and out of the country.