第25题: [单项选择]Material abundance has been the life blood which has ______ Americans in their basic beliefs and values. A. contributed B. provided C. favored D. sustained 参考答案:D 答案解析:[答案详解] 动词辨析。sustain意为“维持(生命、活力等),使……持续”;contribute意为“捐(款),捐助”;provide意为“提供”;favor意为“支持……,赞同……”。