#gmat ultimate grammar book pg40

Hello, sampriya. Although I have not read the book you reference, I can say that the GMAT™ strongly favors active, direct verbs over perfect constructs. That is, unless there is some specific reason to indicate an ongoing action in the present perfect tense or an earlier action than one that had already occurred in the past by using the past perfect tense, you should go with the simpler, terse version of the verb. In this case, there is no reason that found could not work: The plumber located the source of the leak, nothing more, an action that took place in the past. It is not that has found is incorrect, and if the plumber (or someone else) has not fixed the leak, then the leaking itself is an ongoing action, but that there is nothing in the sentence that precludes the more concise found from fitting into the blank instead. (On a personal note, I would only say that a plumber has found a leak if the plumber were physically present; otherwise, I would just use found.)

If you have other grammatical questions, specifically as they relate to the GMAT™, I would be happy to help out.

- Andrew