Question

As 'I' is used to denote a single person but why do we connect it with a plural verb like "I go/do" why not " I goes/does"

Answer 1

We do not do this because there are certain rules of tenses according to which english is written or said ,I.e composed.
Here's a table which you would have learnt in earlier classes or will learn ,which is very helpful for composing sentences with correct tenses.