That event greatly changed his life.

The public prosecutor's office is investigating the incident.

We started an investigation into the incident.

The police are investigating the incident.

The Tiananmen Square incident is an important event in Chinese history.

The Marco Polo Bridge Incident was the trigger for the Sino-Japanese War.

He got involved in a love affair.

This is the most difficult case I have ever faced.

We conducted a questionnaire survey for the development of new products.

The next census will be conducted next year.