The Indefinite form merely shows that the action takes place in the present, past or future. The form of the verb gives no indication as to its duration or completion.
THE PRESENT INDEFINITE
The formation of the Present Indefinite.
1. The Present Indefinite is formed from the infinitive without the particle to.
In the third person singular the ending ‑s is added. After a sibilant represented in spelling by s, ss, ch, sh, tch, x, z and after the vowel o, ‑es is added: he writes, he reads, he speaks; he passes, he pushes, he watches, he teaches; he goes, he does [dAz].
2. The pronunciation of the ending-s (-es) depends on the sound preceding it. It is pronounced as:
[Iz] after the sibilants [s], [z], [S], [C], [G]: passes ["pRsIz], pushes ["puSIz], teaches ["tJCIz], judges ["GAGIz];
[z] after voiced non-sibilants and vowels: reads [rJdz], lives [lIvz], sees [sJz];
[s] after voiceless non-sibilants: works [wWks], wants [wPnts].
3. In the third person singular we find the following orthographical change:
A final у is changed into i if it is preceded by a consonant and then ‑es is added: to study — he studies; to try —- he tries.
After a vowel у is kept unchanged: to play — he plays; to stay — he stays.
4. The interrogative and the negative forms are formed by means of the Present Indefinite of the auxiliary verb to do and the infinitive of the notional verb without the particle to.
Affirmative
Interrogative
Negative
I work
He works
She works
We work
You work
They work
Do I work?
Does he work?
Does she work?
Do we work?
Do you work?
Do they work?
I do not work
He does not work
She does not work
We do not work
You do not work
They do not work