1.   In investigating the causes of absenteeism from work, for example, researchers have found different contributory factors.

2.   It held up tram traffic for several hours, while the police investigated the cause.

3.   Surrey police are investigating the cause.

4.   The commission will investigate the cause of the accident, focusing especially on safety issues.

5.   The government had promised to investigate the cause of the accident.

6.   We therefore investigated the causes of this complication.

7.   The Committee is charged with investigating the causes of the accident.