Make a summary of Oliver Twist. 英语字数：300-800

"Oliver Twist," a novel by Charles Dickens published in 1837-1839, is a social critique of Victorian England through the eyes of an orphan boy. The story follows Oliver from his miserable childhood in a workhouse to his adventures in London, where he encounters various characters who shape his life. The novel begins with Oliver's birth in a workhouse, where he endures a harsh and loveless upbringing. After reaching the age of nine, he bravely asks for more gruel and is subsequently apprenticed to a cruel undertaker. Running away from mistreatment, Oliver finds himself in London, where he falls into the hands of Fagin, a criminal who trains young boys to be pickpockets. Among these boys is the Artful Dodger, who teaches Oliver the tricks of the trade. One day, during a theft, Oliver is wrongfully accused and captured. He is taken in by Mr. Brownlow, a kindly gentleman. Meanwhile, Fagin employs another of his thieves, Bill Sikes, to recapture Oliver so he can continue his criminal activities. Sikes' brutal treatment of his lover, Nancy, leads her to feel sympathy for Oliver and eventually betray Sikes to help Oliver escape. In the ensuing chaos, both Sikes and Nancy meet tragic ends. Throughout these events, Oliver remains unaware of his true heritage. It is eventually revealed that he is the rightful heir to a substantial fortune, the son of a well-to-do family. With this discovery, Oliver's life takes a drastic turn as he gains not only wealth but also a loving family in the form of Mr. Brownlow and his relatives. Dickens uses Oliver's story to criticize the societal injustices of his time, including poverty, child labor, and the flaws of the justice system. "Oliver Twist" is both a thrilling adventure tale and a powerful exposé of the hardships faced by the less fortunate in society, highlighting Dickens' commitment to social reform.