Multimedia teaching means that in the teaching process, according to the teaching objectives and the characteristics of the teaching objects, through teaching design, modern teaching media are reasonably selected and used, and are organically combined with traditional teaching methods to participate in the whole teaching process, and various media information is used on students to form a reasonable teaching process structure and achieve the optimal teaching effect. According to the above definitions, which of the following is not multimedia teaching:. ['Fan Zheng uses Powerpoint courseware in civil servant exam preparation lectures.', 'Zhu Xuelin answers class-related questions to students through video calls.', 'Students learn legal knowledge through a mock court organized by the school.', 'In the 1950s, agricultural technicians explained the planting technology to fellow villagers through a slideshow.']