thinks, thought, was thought, work, works, working This painting

thinks, thought, was thought, work, works, working This painting ______ of as one of the best ______of the famous painter.
【正确答案】：was thought; works
【题目解析】：第一个空格考查的是被动语态，根据条件选择was thought，第二个空格考查名词的数性，work作为作家的著作时为可数名词，结合上下文此处应该为复数，选择works。