第22题: [单项选择]To ______ the world peace has been one of the most crucial functions of the United Nations since it was founded in 1945. A. sustain B. maintain C. contain D. retain 参考答案:B 答案解析:sustain意为“维持”,指继续生存;maintain意为“维护”,指坚持或保持; contain意为“包含”,指包括或由……构成;retain意为“保留”,指保持或维持在一个特殊的场所、条件或位置