单选题 To survive in the intense trade competition between countries, companies must ______ the qualities and varieties of their products to the world-market demand.
【正确答案】 D
【答案解析】[解析] 固定搭配。选项中，只有gear(使适应，使适合)可以接to+名词形式。故答案为D。forfeit“改善”，为不及物动词；enhance“增加，提高”，直接接名词做宾语；guarantee“保证，保修”，后面也不接to。