Long long ago, schoolbags were boxes made of wood (木头) or bamboo (竹子). Students carried these "bags" to school.
In the 1970s, schoolbags were yellow cloth (布) bags. Students carried them. Workers and farmers carried them, too. On the schoolbag, there were big words-Serve (服务) the people. This is the memory (记忆) of the times.
Now our schoolbags are backpacks. They are colourful — red, yellow, black...