English Grammar: An Introduction

Basically there are two types of clauses, MAIN (or PRINCIPAL) CLAUSES [MCl] and SUBORDINATE CLAUSES [SCl].

A main clause is an independent unit which can stand alone as a sentence {Se}. Every sentence must have a main clause. Since simple sentences have only one clause, that clause must by definition be a main clause.

A subordinate clause cannot stand alone as a sentence. It contains further information about some element in the main clause and is linked to the MCl in some way. Thus (3a) and (3b) are not complete units grammatically; only (3c) is acceptable:

The convention for sub-clauses is that their brackets are placed within those of the main clause so that their dependence is clearly indicated. Since sub-clauses can also be subordinated within other sub-clauses, bracketing can become fairly complicated. A golden rule is that brackets come in pairs; if you open a pair of brackets, you must eventually close it. If you do an analysis and end up with five left-facing brackets and only three right-facing ones, then there is something wrong!

A sentence like (3c), which contains a main clause and one or more subordinate clauses, is a COMPLEX sentence.

A sentence which contains two or more main clauses, like (4) below, is a COMPOUND sentence. The two clauses are CO-ORDINATE clauses.The relationship between such clauses is called CO-ORDINATION.

Each of the clauses in (4) could stand alone as a sentence (as they do in (1a) above), and hence has its own independent set of brackets. Notice too the position of the conjunctions. In (4) the conjunction belongs to both clauses equally, and is therefore placed outside the brackets. ( It might have made a difference to Anne Hathaway if the clauses were reversed, but it makes no difference grammatically.) In (3b) the conjunction indicates the type of subordination and is therefore placed within the SCl brackets. If a SCl moves to a new position in a clause, then its conjunction or other marker of subordination moves with it.