He tried to prove it for eight years until he died of cancer in 2001.

John still has to prove it for two or three more years, but I don't think he'll have a problem.

This idea has now been proven wrong for over 100 years.

Therefore we still believe you to be an honest man, as your dealings have proved for many years.

"There are contraceptives that have been proven for 10 years to be effective."

The group proved its best on top of all others for five consecutive years.

He wants teachers to prove themselves for three years to gain tenure.

The theorem will not be proven for almost 123 years, until 1976.

It has proved for 25 years that it is possible.

The term has been proving itself for 40 years now.