An experimental solar power plant will be built in the Australian desert.
Rules are made to be broken.
The cave paintings of Lascaux were made in the Upper Old Stone age.
Mistakes were made.
Insulin was first discovered in 1921 by researchers at the University of Toronto. It is still a treatment available for diabetes.
The actor is unknown.
You want to be vague about who is responsible.
You are talking about a general truth.
The actor is irrelevant.
You want to emphasize the person or thing acted on.
