(2) After an interrogative adverb, adjective, or pronoun, also frequently found:—
What God doth the wizard pray to?—Hawthorne.
What is the little one thinking about?—J. G. Holland.
Where the Devil did it come from, I wonder?—Dickens.
(3) With an infinitive, in such expressions as these:—
A proper quarrel for a Crusader to do battle in.—Scott.
"You know, General, it was nothing to joke about."—Cable
Had no harsh treatment to reproach herself with.—Boyesen
A loss of vitality scarcely to be accounted for.—Holmes.
Places for horses to be hitched to.—Id.