Constituents of clauses. This structured account of sentences assumes the recognition of clauses. A clause consists of central and peripheral constituents, the first usually obligatory, the second optional. The peripheral or marginal constituents are mainly adverbials such as incidentally, also , and last week in Incidentally, Derek also gave me some books last week , and vocatives such as Natalie in I like my tea strong, Natalie . In the kitchen .
Conversations often contain such sequences as That one .
The big one . No, the one over there . Higher up . Such uncertain sequences are often referred to as sentence fragments . Functional and syntactic categories.