Complex sentence: The Hecate Strait or Strait of Hecate (Haida: "Seegaay") is a shallow body of water separating the Queen Charlotte Islands (Haida Gwaii) from the mainland of British Columbia in Canada.
Split into simpler sentences: The Hecate Strait or Strait of Hecate is the name in English name for a shallow body of water called Seegaay in Haida. The strait separates Haida Gwaii, or the Queen Charlotte Islands, from the mainland of British Columbia in Canada.