A Student's Introduction to English Grammar

§2.1 Prepositions vs subordinators 129

Notice first the effect of the NP complement condition on how we have to clas­

sify the word befo re in the three constructions shown in [4]. We compare befo re

with the verb know:

[4] TYPE OF COMPLEMENT

NP

befo re AS HEAD

We left before the last act.

That was before he died.

know AS HEAD

We know the last act.

ii CLAUSE I know he died.

iii NO COMPLEMENT I had seen her once before. Ye s, I know.

In [i] the complement of befo re or know (marked by double underlining) is an NP;

in [ii] it is a subordinate clause; and in [iii] there is no complement. Everyone agrees

that this difference in the complements has no bearing on the classification of know:

it is a verb in all three examples. Know happens to be a verb that licenses either an

NP or a clause as complement, and where the complement is optional.

But traditional grammar treats befo re in a completely different way. It is treated

as a preposition in [i], a 'subordinating conjunction' in [ii], and an adverb in [iii].

We see this triple assignment as an unnecessary complication. It is much simpler to

give befo re a uniform analysis, treating it as a preposition in all three, just as know

is a verb in all three.

Notice in the first place that befo re has the same meaning in all of [i-iii]. Sec­

ondly, it takes the same modifiers in these three contexts. We could, for example,

insert such items as long, shortly, an hour, a short while in front of befo re in all

three examples in [4]. The difference between the three instances of befo re is thus

solely a matter of the complement. Nowhere else in the grammar is a part-of-speech

distinction based purely on a difference of this kind.

Our extension of the preposition category involves redrawing the boundaries

between prepositions and subordinators, and between prepositions and adverbs. We

take up these two pairs in turn.

2.1 Prepositions vs subordinators

The traditional class of subordinating conjunctions contains (among

others) the words in [5]:

[5 ] i after

ii a. although

b. if;

befo re

because

that

since till

ifc lest

whether

until

provided though unless

We need to distinguish two words with the shape if.

One has a conditional meaning, as in I'll help you if[ can: we show this above

as ifc.

The other occurs in subordinate interrogative clauses like See ifthere are any

vacancies, corresponding to main clause Are th ere any vacancies?: we show

it as i/;. This is a variant of whether: compare See whether th ere are any

vacancies.