Liubov and Trofimov argue at the party because (c.) Trofimov says Liubov cant go back to the past.
The Cherry Orchard is a play written by Anton Chakhov and published in 1903. It tells the story of a Russian landowner, who returns to her family estate, and the lives of a group of servants. In the story, Liubov is the landowner, who has a daughter called Anya. Moreover, Trofimov is Anya's love interest. In Act III, during a party, Liubov and Trofimov have an argument after Trofimov tells her that she cannot go back to the past. He asks her to accept the truth and to understand that the house, as well as the cherry orchard, will be sold at an auction.