In the past the workers do a lot of hard work. A. forced B. forced to C. were forced to

问题补充：

In the past, the workers do a lot of hard work.

A. forced B. forced to C. were forced to

答案：

解析：考查时态及语态。句意：在过去，工人们被强迫做许多多艰苦的工作。结合语境及时间状语，可知本句描述的是过去发生的动作，故用一般过去时态。主语the workers是被强迫force的对象，故用被动语态。选C。