What are gold collar, silver collar, pink collar, white collar, blue collar, green collar, gray collar and black collar?

Golden collar-those bosses, of course.

Silver collar-that's a senior migrant worker next to the boss.

White-collar workers-those who often wear white shirts in office buildings.

Pink collar-especially those women with superior working conditions.

Blue-collar-working class, don't you see that workers' work clothes are usually blue?

Grey collar-rag collector, embarrassed all day.