He responds whenever he is called.

In this sentence the Adverb clause is: whenever he is called
and the Subordinating conjunction is: whenever

what is the word modified? how can i figure out which word it is?

Adverb clauses usually modify verbs and tell when, where, or to what extent about the verb.

This clause modifies the verb, "responds," and tells when.

In the sentence "He responds whenever he is called," the adverb clause is "whenever he is called," and the subordinating conjunction that introduces this clause is "whenever."

To determine the word that this adverb clause modifies, you can imagine removing the clause from the sentence and see which word would be affected.

In this case, if we remove the adverb clause ("whenever he is called"), the sentence becomes "He responds." The meaning of the sentence remains intact, showing that the adverb clause is not necessary for the sentence to make sense. This means that the clause is providing additional information and is not directly modifying any specific word in the sentence.

Instead of modifying a specific word, this adverb clause provides information about the circumstances under which he responds. It explains the time or condition when his response occurs, but it does not modify a single word in the sentence.