Complex sentence: Rachel Gurney (5 March 1920--24 November 2001) was an English actress who is best known for playing Lady Marjorie Bellamy on the LWT classic "Upstairs, Downstairs".
Split into simpler sentences: Rachel Gurney (5 March 1920--24 November 2001), an English actress. She was best known for playing Lady Marjorie Bellamy in the classic London Weekend Television serial "Upstairs, Downstairs".