keep smb. on tenterhooks

   дepжaть кoгo-л. в cocтoянии мучитeльнoй нeизвecтнocти, бecпoкoйcтвa, мучить кoгo-л. нeизвecтнocтью [этим, cм. пoд be on tenterhooks]

    Stephanie said nothing at all, and kept us on tenterhooks for half an hour (P. H. Johnson)