代号为喵
不做状语，hostage 做主语补足语。hold 为谓语动词，He是主语， 用了被动语态。把句型还原为Somebody held him hostage for almost a year，更有助于你理解。
爱吃糖z
同学你好！hostage 的确是名词。朗曼词典有：A British journalist was held hostage for over four years.牛津字典里有一句话：Three children were taken hostage during the bank robbery. 有动宾短语hold somebody prisoner/captive/hostage 和held hostage to。你的句子是该短语被动语态的变化。
