I need to ask a question. I am from Pakistan. Here, there are so many adhans being called at time for prayer and they continue for about half an hour to forty-five minutes. Can I continue with my work after listening to one adhan completely and carefully, because it is difficult to listen to all?

Listening to one adhan is sufficient - and making the recommended du’a following it.[1]

Choose the earliest or clearest one according to the proper time.

Reference:

[1] http://islamqa.com/en/search?key=adhan&yt1=search