Which sentence contains an adverb clause?
a. the bookstore is closing for renovations at the end of the month.
b. i visited the bookstore while you were shopping for a computer.
c. we will try to find a good price for a new computer.
d. many stores are having sales throughout the weekend.

b. I visited the bookstore while you were shopping for a computer.

Example:
"Where they can find food easily" is an example of an adverbial clause. It is an adverb of place, answering the question: Where do most animals thrive?

Adjective clauses modify the noun or the pronoun in the sentence's main clause. The first thing to do is to identify the two clauses in the sentence.

First clause: Those may enter the park (the main clause)
Second clause: whose tickets have been punched (the subordinate clause)

Since adjective clauses generally start with a relative pronoun, it is clear that the second clause is the adjective clause. The relative pronoun is "which". Another clue is that adjective clauses are always the subordinate clause. It modifies the pronoun those.