【正确答案】 A

【答案解析】[解析] think后面可以跟带形容词、名词、to be的复合结构做宾语；如果宾语是不定式须后移，则用形式宾语it填补。此处的不定式自身带有逻辑主语，用介词for引导，如：A lazy sheep thinks its wool heavy. Jonnie thought this good advice. We all thought him to be a wealthy man. He might think it polite (for him) to return the visit.