Give students some very simple three- or four-word SVO/C sentences from the unit (or make some yourself) and ask them to add as many phrases and clauses as they can to make a long complex sentence. Who can make the longest sentence?
For example:
Children will learn. g It has been commonly recognized by educationalists, and confirmed by research over the last century by such figures as Piaget and Vygotsky, that children, when given the freedom to do so, will learn through active interaction with their environment. (39 words)