be useful

References in classic literature ?
These we have now mentioned in general, but to enter into particulars concerning each of them, though it might be useful to the artist, would be tiresome to dwell on.
Susan tried to be useful, where she could only have gone away and cried; and that Susan was useful she could perceive; that things, bad as they were, would have been worse but for such interposition, and that both her mother and Betsey were restrained from some excesses of very offensive indulgence and vulgarity.
In this occupation she hoped, moreover, to bury some of the recollections of Mansfield, which were too apt to seize her mind if her fingers only were busy; and, especially at this time, hoped it might be useful in diverting her thoughts from pursuing Edmund to London, whither, on the authority of her aunt's last letter, she knew he was gone.
SOCRATES: And in supposing that they will be useful only if they are true guides to us of action--there we were also right?
It would therefore be useful if Shooting Times could run articles a few times a year providing details on how to form cases and other useful "tricks" from the past.
The 42-year-old hopes she will be useful to co-star Tess Daly, who is replacing Bruce Forsyth when the BBC1 hit returns in September.
Immunohistochemical detection of rickettsial antigens may be useful in diagnosing ATBF.
I do think that it is good for you (readers and authors) to have a little better idea of what you are getting with a new editor, and, as a counselor, I do think that a little appropriate disclosure can be useful.
Here it might be useful to compare Noguchi's "design" work with that contemporaneously produced by Charles and Ray Eames for Herman Miller.
It certainly would be useful if he was, but it is not necessary.
If the patient has difficulty clarifying a feeling, expressing how you would have felt can be useful.
Photographs certainly can be useful, but use them prudently and with full knowledge of those being photographed.