ask (something) of
To request something of another person. I hope she doesn't ask that of me—I'm afraid I won't be able to say no. I'm sorry, but I'm not sure. Ask those questions of the boss.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
ask something of someone or something
to request or demand something from someone, something, or a group. I want to ask something of you. We will ask that of the board of directors. You should ask that of your database.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.