We will discuss further topics – the relationship between main and subordinate clauses, the characteristics of subordinate clauses and the question of non-finite clauses.

Main and subordinate clauses

One very traditional view of subordinate clauses is that they derive from main clauses which are put into subordinate positions in sentences and undergo certain syntactic changes. In many languages other than English, they also undergo morphological changes, since a given verb turns up in one shape in main clauses and another shape in (particular types of ) subordinate clause. This is easily demonstrated via the French elle peut ‘she can [main clause]’ and afin qu’elle puisse ‘so that she can [subordinate clause, an adverbial clause of purpose]’, where only puisse occurs in adverbial clauses of purpose and only peut occurs in main clauses.

The relationship between main and subordinate clauses was foreshadowed in the discussion of rules of thumb. There, we saw that when a complementiser is removed from an adverbial clause or a complement clause in English it leaves a sequence of words which make up a complete main clause. The removal of the complementiser from relative clauses, however, leaves a sequence that lacks either the noun phrase which would be to the left of the verb or the noun phrase which would be to the right of the verb. A second complication is that WH words seem to be both pronouns and complementisers, whereas that is purely a complementiser.

One way of handling the relationship is to assume that the route from main clause to relative clause is as follows in (1).

Assume that the source of the relative clause which Mrs Dashwood accepted is Mrs Dashwood accepted which, with the pronoun which in the usual slot for direct objects. The pronoun which is moved to the front of the clause, in fact to a special slot for complementisers outside the main body of the clause. This enables us to show both that which is the direct object of accepted and that it is the complementiser of the relative clause. (This treatment appeals to the idea introduced on constructions: they can be thought of as arranged in a network with specific paths through the network from construction to construction. We looked only at main clauses, but the idea is here extended to the relationship between main and subordinate clauses.) The analysis of relative clauses can be made more complex if we take at its face value the definition of pronouns as substituting for nouns – more accurately, for noun phrases. One line of analysis would take the source of the above relative clause to be Mrs Dashwood accepted the cottage, with which being substituted for the cottage and then being moved to the complementiser slot.

Relative clauses with the complementiser that have a different source. Since that is not a pronoun, there is no reason to start with it in subject or object position and then move it. In the source main clause, it is in the complementiser slot. But in the source main clause, accepted needs an object. We solve this problem by assuming that the source main clause is that Mrs Dashwood accepted it. En route to the relative clause, it is dropped.

We have space to discuss only one simple example. Anyone who takes further this sort of analysis quickly finds that the details of even short examples are not straightforward. Furthermore, the analysis sketched above is fairly superficial; attempts to gain depth inevitably lead to analyses that are both very detailed and very abstract. One final point in this section, it is tempting to think of moving backwards and forwards along the paths through the network of constructions, and it is equally tempting to think of being able to move from main clause to subordinate clause or vice versa. In practice, all recent detailed analyses of syntax of this type specify paths from a source construction, a starting point, out through the network to more complex constructions, and not in the opposite direction.