来自词根fact, 做，词源同fact,effect. 即做事情的必要条件，因素，要素等。

1. Stress, both human and mechanical, may also be a contributing factor.

来自人的和机械方面的压力可能也是一个因素。

2. Environmentalists say a critical factor in the city's pollution is its population.

环境保护主义者说造成该城市污染问题的一个关键因素是其人口数量。

3. This factor will come increasingly to the fore as election day nears.

随着选举日的临近，这一因素将愈发重要。

4. Obesity is a major risk factor in many diseases.

肥胖是引发多种疾病的重要因素。

5. A key factor in running a business is the delegation of responsibility.

公司经营中的一个重点就是职责的分派。