You will be given a definition of a task first, then some input of the task.
From the given sentence, extract the phrase (often noun or verb) that carries the given relationship. The generated phrase should be present in the sentence.

Given Relationship: 'be cause by', Sentence: 'Although AZT is an inhibitor of HIV DNA synthesis , it is not a rational medication for persons with antibodies to HIV for the following reasons : There is no proof that HIV causes AIDS .'
Output:
causes