237 Other uses of should

A After can't think why/don't know why/see no reason why etc. when the speaker queries the reasonableness or justice of an assumption:

/ don't know why you should think that I did it.

I see no reason why you should interfere in their quarrel. The perfect infinitive is usual when the assumption was in the past:

/ can't think why he should have said that it was my fault.

В Idiomatically with what, where, who in dramatic expressions of surprise:

What should I find but an enormous spider! Quite often the surprise is embarrassing: Who should come in but his first wife!

С After lest and sometimes after in case:

1 In literary English lest . . . should is sometimes placed after expressions of fear or anxiety:

He was terrified lest he should slip on the icy rocks. should + perfect infinitive is used when the anxiety concerns a previous action:

She began to be worried lest he should have met with some accident.

о lest can also be used in purpose clauses to mean 'for fear that': He dared not spend the money lest someone should ask where he had got it.

As above, this is a literary form.

in case, which is more usual than lest here, can be followed by should or by an ordinary present or past tense:

in case someone should ask/someone asked (See also 227, 337.)

D should is sometimes used in purpose clauses as an alternative to would/could:

He wore a mask so that no one should recognize him.

(See 336.)

E In conditional sentences instead of the present tense:

If the pain should return take another of these pills. (See 224.)

F In indirect, rather formal, commands when the recipient of the command is not necessarily addressed directly:

He ordered that Tom should leave the house. (See 321 B.) Compare with He ordered Tom to leave which implies that he told Tom himself.

23 The infinitive

238 Form

A Examples of infinitive forms

Present infinitive	to work, to do
Present continuous infinitive	to be working
	to be doing
Perfect infinitive	to have worked, to have done
Perfect continuous infinitive	to have been working
	to have been doing
Present infinitive passive	to be done
Perfect infinitive passive	to have been done

В The full infinitive consists of two words, to + verb, as shown above. But after certain verbs and expressions we use the form without to, i.e. the 'bare infinitive' (see 246):

You had better say nothing. (See 120.)

С It is not normally advisable to put any words between the to and the verb, but see 248, split infinitives.

D To avoid repetition, an infinitive is sometimes represented by its to: Do you smoke? ~ No, but I used to (smoke). (See 247.)

239 Uses of the infinitive

A The infinitive may be used alone, We began to walk, or as part of an infinitive phrase, We began to walk down the road.

В The infinitive may be the subject of a sentence (see 240).

С The infinitive may be the complement of a verb: His plan is to keep the affair secret.

D The infinitive may be the object or part of the object of a verb.

It can follow the verb directly: He wants to pay (see 241, 243) or follow verb + how, what etc. (see 242) or follow verb + object: He wants me to pay (see 243, 244).

E be + infinitive can express commands or instructions (see 114). F The infinitive can express purpose (see 334).

G The infinitive can be used after certain adjectives: angry, glad, happy, sorry (see 26) fortunate, likely, lucky (see 27)

H The infinitive can connect two clauses (see 249). I The infinitive can sometimes replace relative clauses (see 77, 250). j The infinitive can be used after certain nouns (see 251).

К The infinitive can be used with too/enough and certain adjectives/adverbs (see 252).

L An infinitive phrase such as to tell the truth, to cut a long story short can be placed at the beginning or end of a sentence (see 253).