TOKYO/SINGAPORE (Reuters) – Oil prices fell sharply in early trading on Monday after Greece rejected austerity measures demanded in return for bailout money and as China rolled out an unprecedented series of steps over the weekend to prevent a full-blown stock market crash. In China, stock markets face a make-or-break week after officials rolled out a series of measures to prevent a full-blown stock market crash that would threaten the world’s second-largest economy. It adds an extra negative factor on top of the turmoil in Chinese financial markets, the recent rise in U.S.