题目

I wonder what it feels like to be one of _______ really rich. The Browns already have two Rolls-Royces and now they are buying _______ third. A. the; the    B. 不填; a     C. the; a       D. 不填; the   答案：C设函数f（x）=则满足f（x）≤2的x的取值范围是   [     ]A．[﹣1，2]B．[0，2]C．[1，+∞）D．[0，+∞）