SUBSTITUTION
Substitution likewise avoids the repetition of recoverable information; but while ellipsis leaves a structural slot empty, substitution replaces it by a ‘filler’ word. Consequently, the exact words which have been ellipted are not recoverable. A commonly used clausal substitute is do so, as in 1 below. This is not acceptable, however, where the verb is not agentive (for instance, know, like) and in such cases ellipsis is used, as in 2.
1 You can hire a self-drive car, but I wouldn’t advise you to do so. (i.e. hire a self-drive car)
2 Some people like mangoes, others don’t. (*don’t do so).
So substitutes for clause complements after verbs such as say, hope, think, expect, be afraid, suppose and believe. Not is the negative substitute with hope, be afraid and suppose:
Is it going to rain tomorrow? The weather man says so (i.e. that it is going to rain).
I hope not. (i.e. that it’s not going to rain).
So can also be used as an alternative to an auxiliary + too to substitute positively, just as neither alternates with auxiliary + either to substitute negatively:
This hair-dryer makes an dreadful noise. So does mine./Mine does too./Mine too.
I wouldn’t like to live in this climate. Neither/Nor would we./We wouldn’t either.
Ellipsis and substitution in nominal groups
In nominal ellipsis we replace the head element by pronouns such as these, any, each, all, both, either, neither, none (I’ll take these, There aren’t any left); possessives such as John’s, and numeratives such as the first, the next three. Nominal substitution makes use of one/ones (I prefer the dark one(s)) this, that and the pronouns (an)other.
