Complex sentence: Nick subesquently has to endure having to lunch with Widmerpool and fending-off questions about Widmerpool from his prospective in-laws becomes for Nick a recurring theme throughout the novel.
Split into simpler sentences: Nick subesquently has to endure having to lunch with Widmerpool. Fending-off questions about Widmerpool from his prospective in-laws becomes, for Nick, a recurring theme throughout the novel.