Whats a correct principal part of a verb , and infinitive part of a verb?

Verbs have three principal parts, although some dictionaries and grammars list four. So I'll show you four in case that's what you are supposed to know.

For "regular" verbs:
Base form = walk
Simple past = walked
Past participle = walked
Present participle = walking

For "irregular" verbs:
Base = go
Simple past = went
Past participle = gone
Present participle = going

More information is here: http://grammar.ccc.commnet.edu/grammar/verbs.htm

The infinitive is simply the base form with the word "to" in front of it:

to walk
to go
etc.

=)

The correct principal parts of a verb refer to the different forms of the verb that are commonly used in various tenses and moods. In English, verbs typically have three principal parts: the base form, the simple past form, and the past participle form. Some dictionaries and grammars may also include a present participle form as a fourth principal part.

For regular verbs, the base form remains the same, while the simple past form is created by adding "-ed" or "-d" to the base form. The past participle form is also created by adding "-ed" or "-d" to the base form. For example, the verb "walk" has the base form "walk," the simple past form "walked," and the past participle form "walked." The present participle form is created by adding "-ing" to the base form, resulting in "walking."

Irregular verbs, on the other hand, do not follow a consistent pattern for forming their principal parts. For example, the verb "go" has the base form "go," the simple past form "went," the past participle form "gone," and the present participle form "going." These irregular verbs have unique forms for each principal part that must be memorized.

The infinitive is a different aspect of the verb and is formed by adding the word "to" in front of the base form. For example, the infinitive form of "walk" is "to walk," and the infinitive form of "go" is "to go." The infinitive is often used to express purpose or intention.

When determining the correct principal part or infinitive form of a verb, it is helpful to consult a reliable dictionary or grammar resource. These resources will provide a comprehensive list of principal parts for both regular and irregular verbs, as well as the correct formation of infinitives.