Sentence examples for this is a theory from inspiring English sources

"This is a theory," he emphasizes.

"This is a theory without a witness".

This is a theory I once subscribed to.

This is a theory Fried has expounded before.

"This is a theory without a case," Mr. Brafman said.

This is a theory expounded by a Japanese physicist and historian, Mitsutomo Yuasa, in the 1960s.

This is a theory-driven paper with suggested theoretical model and case study research design.

This was a theory worthy only of fiction — of a character as deranged as Woody Harrelson's, perhaps, but nobody I've ever met.

But this was a theory, implicating the highest levels of the Russian government, that the British government did not want to pursue.

"This was a theory that he put up on Monday this week.

This was a theory inconsistent with Chief Seedman's previous certain belief that Johnson had not acted alone.