Linking verbs connect the subject of a sentence to a noun or adjective that renames or describes the subject. Examples include:
* be (am, is, are, was, were, being, been)
* seem
* appear
* become
* feel
* look
* sound
* taste
* smell
Auxiliary verbs help form verb phrases and indicate tense, mood, or voice. "Should" helps express obligation, suggestion, or possibility.
Example:
* Should you go to the party? (Should is an auxiliary verb helping the main verb "go")
* You should be happy. (Should is an auxiliary verb helping the linking verb "be")
It's important to note that:
* "Should" can sometimes appear in a sentence with a linking verb, as in the second example above. However, "should" itself is not the linking verb in that sentence.
* The verb "should have" is a modal auxiliary verb used to express a past obligation, suggestion, or possibility. It is not a linking verb.