Complex sentence: On 20 November 1979, the United States requested the cancellation of Koziy's certificate of naturalization on the grounds that Koziy had illegally procured his citizenship by concealment of a material fact or by willful misrepresentation by failing to disclose his involvement in the occupational police in Ukraine.
Split into simpler sentences: On 20 November 1979, the United States requested the cancellation of Koziy's certificate of naturalization. The United States alleged that Koziy had illegally procured his citizenship by concealment of a material fact or by willful misrepresentation by failing to disclose his involvement in the occupational police in Ukraine.