During his career he frequently testified to Congress on environmental and oceanographic issues.

He has frequently testified before Congress, taking pains to carve out relationships there.

He frequently testified in trademark cases as an expert.

As head of a mass transit riders' advocacy group in the 1950's, he frequently testified at public hearings.

He frequently testified about some event or date during the war, only to say under questioning that he had no recollection.

Hastings frequently testified before government bodies about railroad rates.

He has testified frequently before the armed services, foreign relations, and homeland security committees of both houses of Congress.

He frequently testifies before Congress and the courts on issues involving Indian gaming.

He served for many years as a consultant to government agencies dealing with drug problems and testified frequently on legislation seeking to curb illicit drugs.

The influence of Bacon on the Royal Society is frequently testified to by its members.