Which part of speech is “long” in the sentence below? My grandmother loved to take long walks in the woods with me.

adjective

Explanation:

In this case, long would be an adjective.

Adjectives give more information to what it is describing. A sentence can function without an adjective as you can think of it as embellishment. It enhances your writing but is not necessary.

Let us take out long from the sentence:

My grandmother loved to take walks in the woods with me.

There is less description about the length of the walks, but the sentence grammatically functions.

Long is an adjective

I hope this helps! Please let me know if you have any further questions :)