幾時要加s 或 es ??

Peter never goes with the tide.

This sentence uses the simple present tense. In this tense, add s/es when necessary.

I do not think that there is a rule for adding s/es. But it is easy to recognize and tell when you see the sentence.

For example: Mum washes the dishes everyday.
I play football every evening.

The most important is that you should read more English books!!
Remember the following table:
when the sentence uses simple present tense:
I, we, they, you ---------------------------- infinitive (no s/es is added)
He, she, it ---------------------------------- add s/es to the verb

「never」 lee個字係用於現在式到，而peter=he，he係現在式的時間，verb用加「es」~

而點解唔係+「s」係因為英文上，「S」，「X」，「O」尾o既字係+「es」的~