There are "7" of them--the 4 "oy" verbs (voy, soy, doy, estoy) and the 3 "-aber" verbs (saber, caber, haber).Really, "caber" is not "irregular" for present subjunctive because it follows the formation for a presente tense verb in the subjunctive mood. 1. Go to yo (form--present tense indicative; 2. Drop the -o; 3. Add opposite endings: -ar>e endings; -er/-ir> a endings. That's it.
- Soy < SER> sea is the "yo" form
- Voy< IR> vaya is the "yo" form
- Doy < DAR> dé is the "yo" form [There is an accent on this form, otherwise, it means "of, from."]
- Estoy< ESTAR> esté is the "yo" form [all Es are accented to é except for nosotros= estemos]
- Saber> sepa is the "yo" form
- Caber> quepa is the "yo" form
- Haber> haya is the "yo" form; it is also the "impersonal" form: "there is/there are"
Here is another way to memorize the present tense irregulars by their "yo" form:
Dé, esté
Vaya, haya
Quepa, sepa
Sea
¡ suerte!
Phillip Dean JD