Application of the 2 verb rule

Question

I'm struggling to understand the application of the 2 verb rule regarding the following sentences:

1. I kept trying.
2. I kept trying to leave.

In the 1st sentence, why is the verb 'to try' not in the infinitive form? As for the 2nd sentence, why is the 3rd verb, 'to leave' in infinitive form instead of the verb 'to try'?

The 2 verb rules states that the second verb following the first in a sentence is written in the infinitive form. For example: I like to sleep. So the 1st verb 'to like' is conjugated whereas the 2nd verb 'to sleep' is left in its infinitive form.

Answer 1

There can be more than two verbs in a clause: "I would have been trying to sleep." But only one can be a finite verb, in other words only one is conjugated by number and person. But there are several nonfinite verb forms. The infinitive is one of them: "I want to sleep". Another is the gerund: "I am sleeping", and another is the participle: "I have slept." So the rule should really be that if there is more than one verb in a clause, only one is finite and the rest are nonfinite (not the same as infinite).

Answer 2

To keep means to continue doing. According to this definition, it's a verb usually followed by the -ing form of the verb.

He keeps trying to distract me.

I keep on thinking I've seen her before somewhere.

I kept hoping that he'd phone me.

Whereas the verb try can be followed by both infinitive and gerund, but here the native speaker would avoid the latter.

I kept trying (to do what?) to leave.