Put ADV over the adverbs, and M over the word (s) it modifies.

The lion tamer glanced nervously at the animals in the cage

ADV: nervously; M: glanced.

Explanation:

Adverbs are words that modify either verbs or adjectives, and give more information about them. They usually answer the questions such as when, where, why, how, etc.

In the example above, in order to find the adverb, we need to ask ourselves - How did the lion tamer glance at the animals in the cage? And the answer will be nervously, which is the adverb.

The word this adverb modifies (or describes) is the verb glanced. Again, you can ask a question - What did the lion tamer do nervously? And the answer will be glanced, which is the verb being modified.