Complex sentence: An expert on puzzles of all kinds, in 1993 Boolos he reached the London Regional Final of the "Times" crossword competition, where his score was one of the highest ever recorded by an American.
Split into simpler sentences: An expert on puzzles of all kinds, in 1993 Boolos reached the London Regional Final of the "Times" crossword competition. His score was one of the highest ever recorded by an American.