An adnominal clause always requires a noun, and is therefore weak in independence compared with other subordinate clauses. There are also expanded clauses which have their structure expanded by use of adnominal forms or nominal forms of verbs. Many expanded clauses are grammaticalized as mood forms of verbs. In Chapter 5, the inner structure of clauses is investigated. It is noticeable that what kind of elements can be included in subordinate clauses depends not only on form but also on function and meaning.
Conditional clauses are larger than manner clauses, and can include subject.
And reason clauses, concessive clauses, opposite clauses are even larger, in this order, and become progressively similar to the structure of main clauses. Chapter 6 discusses the hierarchy among clauses. Subordinate clauses differ according to what kind of subordinate clauses can be included mutually. From this viewpoint, also, manner clause are the smallest, while opposite clauses are the most similar to main clauses. Chapter 7 describes the relationship between the structure of integrating sentences and mood and modality.