1.   Many people doing boring or repetitive jobs deliberately introduce a certain amount of stress to make the routine more exciting.

2.   Thus occupied on this repetitive job, the mind is free to wander and daydream.

3.   ...factory workers who do repetitive jobs.

4.   Each company has a machine to evaluate Pap smears, a repetitive job that in the United States is done entirely by human judgment.

5.   Each company has a machine that evaluates Pap smears, a repetitive job that in the United States is done entirely by humans.