A simple English sentence (‘Birds sing’) consists, apart from intonation, of a single ‘clause’. A compound sentence consists of two or more clauses; a complex sentence has a clause as head and often has a clause included in the attribute. (203-204)
- Hockett (1958), Pag. 203

The axis in a conjunctive construction is a ‘clause’, usually, though not always, a composite form built by a predicative construction. Since clauses and objects are different kinds of forms, prepositional and conjunctive construction can be distinguished even when the directive particle is one of that can be used in either: ‘after’, ‘before’, ‘since’, ‘until’, ‘for’, colloquially ‘like’, ‘than’. ‘Until he comes’ is conjunctive, ‘until tomorrow’ prepositional, because ‘he comes’ is a clause and ‘tomorrow’ is not.
- Hockett (1958), Pag. 194