The workers were organized into a chain-gang and forced to repair roads under the scorching sun.

chain-gang 是由 chain（锁链）和 gang（一群人）组成的复合名词。chain 在这里象征"束缚"或"强制"，gang 指"一群被组织起来的人"。 chain-gang 特指"锁链囚犯队"，历史上指被锁链拴在一起强制劳动的囚犯群体，现在也用来比喻被强制劳动的工人队伍。