单选题 I am not sure whether I can gain any profit from the investment, so I can't make a (n) definite promise to help you.
【正确答案】 D
【答案解析】definite意为“明确的,一定的”,A意为“准确的”;B意为“被定义的”;C意为“显然的”。只有D.sure有“确定的”之意,与划线词意思最接近。