He took the test yesterday is it adverb or adjectives

The adverb is "yesterday." It tells WHEN he took the test -- so modifies the verb "took."

In the statement "He took the test yesterday," the word "yesterday" functions as an adverb. Adverbs modify verbs, and in this case, "yesterday" modifies the verb "took" by indicating when the action occurred.

To determine whether "yesterday" in the sentence "He took the test yesterday" is an adverb or an adjective, you can follow these steps:

1. Identify the word in question: "yesterday"
2. Determine its role in the sentence: In this case, "yesterday" is providing information about the time of when the action took place.
3. Consider its function: An adverb modifies a verb, adjective, or another adverb, whereas an adjective modifies a noun or pronoun.
4. Apply the function to the word: "Yesterday" is not modifying a noun or pronoun; instead, it is modifying the verb "took." Therefore, "yesterday" is an adverb.

So, in the sentence, "He took the test yesterday," the word "yesterday" acts as an adverb.