Verbs ending in -étrer have an alteration (é -> è) in some forms (before a silent syllable except for the future and conditional forms) : pénétrer / il pénètre but il pénétrera, il pénétrerait.
12 verbs follow this model. Below an extract:
To see other models, refer to Model Table
Based on the ending, you can identify features that different verbs have in common. Click on the verbs above to see their conjugation tables and explore their conjugation patterns.