The primary group refers to a social group formed by face-to-face interaction with intimate interpersonal relationships and strong emotional colors; the second group refers to members whose members come together for a specific purpose and are bound by clear rules and regulations. Social groups that form formal relationships. Based on the above definitions, Which of the following relate to subgroups:. ['Xiao Zhao is going to school in a big city, and the folks in the mountains all go to the village entrance to see him off.', "After 20 years, Xiao Zhang's childhood companion established a WeChat group.", 'Friends and relatives came to the scene to cheer Xiao Li.', 'Xiao Wang was admitted to graduate school, and colleagues of the company celebrated him together.']