Manger is a regular -er verb with one orthographic trap (nous mangeons); boire is fully irregular. Both are used with partitive articles and in habits, preferences, and planning.
Manger — regular -er with spelling adjustment: je mange, tu manges, il/elle/on mange, nous mangeons, vous mangez, ils/elles mangent. The -ge- is preserved before -ons to keep the soft /ʒ/ sound: nous mangeons (not *mangons). Same pattern: voyager → nous voyageons, nager → nous nageons. Boire — irregular: je bois, tu bois, il/elle/on boit, nous buvons, vous buvez, ils/elles boivent. The stem changes: boi- (sg. + 3rd pl.) vs buv- (nous/vous). Common expressions: manger dehors (eat out), manger sur le pouce (eat on the go), boire à la santé de (drink to), boire un coup (have a drink).
Which form fills the blank?