Is marked and tax an adjective?

"Marked" and "tax" are not adjectives in the phrase "marked and tax." They are verbs acting as part of a compound verb.

Here's why:

* Marked: This is the past participle of the verb "to mark." It's being used as part of a compound verb with "tax," meaning "to mark and tax."

* Tax: This is the present tense of the verb "to tax." It's also part of the compound verb "mark and tax."

Example:

"The items were marked and taxed at the checkout."

In this sentence, "marked" and "taxed" are acting as verbs, describing the action of marking and taxing the items.