ferō, ferre, tulī, lātum = carry, bear is a highly irregular verb that sort of follows 3rd conjugation rules. In many of its forms, there are missing connecting vowels.
Connecting vowels are missing from many of its present tense indicative forms:
Present Active Indicative
Present Passive Indicative
1st s. “I”
ferō
I carry
feror
I am carried
2nd s. “you”
fers
you carry
ferris
you are carried
3rd s. “he/she/it”
fert
he/she/it carries
fertur
he/she/it is carried
1st pl. “we”
ferimus
we carry
ferimur
we are carried
2nd pl. “you”
fertis
you (pl) carry
feriminī
you (pl) are carried
3rd pl. “they”
ferunt
they carry
feruntur
they are carried
Present subjunctive uses fer- + -a- like a normal 3rd conjugation verb.
Imperfect indicative uses the stem fere- + -ba- as normal.
Imperfect subjunctive uses the infinitive ferre + endings as normal.
Future indicative uses fer- + “one a, five e” as normal.
Perfect, pluperfect, and future perfect (including subjunctive) are normal, but it’s extra important to memorize the 3rd and 4th principal parts because they’re so different from the 1st and 2nd.
Present infinitives are irregular: active is ferre (“to carry”); passive is ferrī (“to be carried”).
Imperatives are irregular: singular is fer; plural is ferte.