那群被铁链锁在一起的囚犯正在烈日下修建铁路。

The ___chain-gang was working on the railroad under the scorching sun.

那些工人像囚犯一样被组织成苦力队，被迫在烈日下修路。

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