When did Yao Mulan begin to like Zeng Xinya at the end of Smoke in New Beijing?

According to the 24th episode of Tencent video official website, "Clouds in New Beijing", Mulan was introduced and asked why Mochow was suddenly so serious about her lessons. Mochow told her about Kong Lifu, a teacher of Chinese studies, and Mulan also said that she had a crush on someone now, that is, Zeng Xinya. The TV series Clouds in New Beijing tells the stories of three families living in Beijing: Yao Siyuan, who represents wealthy Teamin Between, Zeng Wenpu, who represents clean flow, and Niu Sidao, who represents corruption. In this turbulent era, these three families witnessed the story of China people's transition from feudalism to democracy.