do somebody a good turn
do (someone) a good turn
To do something that helps, aids, or benefits another person. If you do someone a good turn, they are much more likely to help you out in the future. John did me a good turn last year, so I'd like to return the favor somehow.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
do somebody a good ˈturnbe helpful to somebody; do somebody a favour: I did you a good turn, now you do me one.
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