Quirk's CGEL (p.1171) classifies "B8 They want us to help." under Type SVO (To-infinitive+S as O), where "us" is supposed to be the semantic subject of the verb "help." If so, what exactly is supposed to be the single O (object) in this sentence? Is it "us to help" as a whole?
16.41 [B8] Complementation by to-infinitive clause (with subject) The verbs in this group (as distinct from the apparently similar 'object + infinitive' construction; cf 16.50) are restricted to a small number chiefly denoting (not) liking or wanting: (can't) bear, desire, hate, like, love, prefer, want, and wish:
- They don't like the house to be left empty.
- I wouldn't want you to lose your way.
After these verbs, the noun phrase preceding the infinitive cannot be made the subject of a passive main clause: *The house isn't liked to be left empty (by them).
There is moreover an alternative construction (chiefly restricted to AmE) in which the noun phrase is preceded by for which marks it as the subject of an infinitive clause, rather than as object of the main clause:
- Jack prefers for his wife to drive the truck. (esp AmE)
These two observations point in the direction of a monotransitive analysis of such verbs. (p. 1193)