Il en a vu de grises = He had an unpleasant time of it.
Il lui en a fait voir de grises = He plagued him terribly.
Grive
*Faute de grives on mange des merles = Half a loaf is better than no bread. (See [Aimer].)
Gros
Ils se sont dit de gros mots = They came to high words; They insulted (slanged) one another.
La servante fait le gros de la besogne (or, la grosse besogne) = The servant does the heavy work.
Il n’a qu’un gros bon sens = He has only plain common-sense.
Vous avez touché la grosse corde = You have come to the main point.
Vendre en gros et en détail = To sell wholesale and retail.