单选题 In spite of a few strikes at the assembly plant during the first quarter of the year, the output remained constantly ______.

【正确答案】 C

【答案解析】去掉空格前面的副词constantly，和空格有关联的是remain。remain是用于“S+V+P”形式的动词，后面可加形容词做表语。形容词steady在这里做表语，修饰的是主语output，意为“产量稳定”。