Learn English – When I have to use verb with “to” and when without

When you use an auxiliary verb for a third person, the main verb loses its 's.'

He walks toward a church
He does walk toward a church.

However, this change doesn't happen in first person; because, there is no 's' in the verb.

I walk toward a church
I do walk toward a church.

Especially when you are forming a question, the auxiliary verb is mandatory.

He walks toward a church? ~ Not a preferred structure as a question.
Does he walk toward a church? ~ Preferred structure

Why? Well, the questions are formed that way only.

It doesn't seem safe

You don't put 'seems' there because, as I said, when you put an auxiliary 'does' there, you remove 's' from the verb. Remember that way - the main verb's 's' is eaten by the auxiliary verb. But remember, this is not always a case.

Given I am X, what's valid for X is in almost all cases is the following:

• an adjective (I am hot, I am third, I am ready)

• a noun or pronoun (I am a cat, I am a worker, I am him, I am George)

• a verb's present participle form, these always end in -ing (I am walking ..., I am envying ...)

• a verb's past participle form if it makes sense to express a state and can also work as an adjective (I am destroyed, I am surprised)

• rarely, a preposition (I am of the tribe, I am to lead my group)

• any of the above with an adverb in front, (e.g. I am very X)

Adverbs can appear between I and am, like really, definitely, etc.

What X can't never be is the plain form of a verb.

So you can say I am walking but never I am walk.

You can say I am to walk but not I am walk.

You can say I am cooking hamburgers or I cook hamburgers but never I am cook hamburgers.

You also are required to express am in all the above situations. Am is not optional, but it's often said in the contracted form I'm.