Verbs are a necessary part of every sentence. Every subject in a sentence must have a verb. Verbs present themselves in the many different ways, but as a part of a sentence, we recognize the following forms of verbs:

As tenses: past,  present and future, and as aspects of these tense forms: simple, continuous (or progressive), perfect, perfect-continuous.
As  moods: indicative, subjunctive, imperative
As voices: active and passive

You must also consider the word function when you are looking for a verb. Sometimes in English a word is used as a noun, or a  verb, or one of the other 8 parts of speech.
The beast was hedged in. (a verb)
The hedge prevented the beast from escaping. (a noun)

You need to understand the function that a word provides in a sentence before you identify it by a grammatical terms. It is the FUNCTION of the verb in the sentence that determines what kind of verb it is.

action versus linking verbs

Action verbs talk about action, linking verbs do not do this. You know the difference when you know  the function of the word.

Run, swim, watch – these words are expressing action – they are something that somebody or something can do.  So, words like these are called action verbs.
Mat  is climbing Mt Kiliminjaro next summer.

This is something Mat can, and hopefully will, do. He can climb.

Linking verbs do not express action. They link the subject of a verb to information about the subject.
Jenny is an Olympic gold medalist.

With linking verbs like ‘ is, are, becomes, am, were, has been, are being, might have been’, etc,  these words are not expressing an action.

Some words  can be both action verbs and linking verbs, their function determined by their function in the sentence. If you can replace such words with  ‘am, is, or are’ for the verb and the sentence is still sound correct, this is a linking verb. Here are some of the most commonly used linking verbs.
feel
taste
look
smell
appear
grow
remain
stay
turn
seem
sound
become
prove

If you do replace a word with am, is, or  are and the sentence makes no sense, the word is functioning as an action verb.
Sharon broke the necklace.
Sharon is not the necklace, so broke is an action verb

Verbs used as Linking or Action Words
State of being verbs can be used as linking verbs or action verbs. contain verbs that are used as either linking or action verbs.
1. The dog looked hungry. (linking verb)
2. The dog looked for a bone. (action verb)

The many forms, functions of verbs demand that you understand how they are used before ascribe it with it correct grammatical term.