翻译原文：

China is not intentionally manipulating its currency to gain an unfair trade advantage but its massive buildup of foreign reserves raises risks for the global economy, a U.S. government report said Wednesday.

In a much-anticipated semiannual report, the Treasury stopped short of labeling Beijing a currency manipulator, which could trigger sanctions under U.S. law.

 But the report said China's buildup of reserves is flooding the country with liquidity and raising risks of a "boom bust" cycle that may harm the global economy.

 The report was unlikely to dampen the efforts by some in the U.S. Congress to take action against China for what many see as maintaining an undervalued currency, the yuan.

The report said that despite "heavy foreign exchange market intervention" by Beijing, U.S. authorities concluded that even though the yuan is undervalued, "China did not meet the technical requirements for designation" as a currency manipulator.

It said U.S. officials were "unable to determine" if the exchange rate policies were "carried out for the purpose of preventing effective balance of payments adjustment or gaining unfair competitive advantage in international trade."

Nonetheless, the report had harsh comments for Chinese authorities, saying that further exchange rate flexibility "is a matter of international interest and responsibility, with critical implications for the smooth functioning of the world's trading system and the adjustment of global imbalances."