What is the difference in meaning between the following two sentences?
They have been exempted from paying tax.
They are exempted from paying tax.
Are both sentences grammatically correct?
The first implies that they, at some unknown past point in time, were exempted from paying tax, and they probably still are to this day (but not definitely).
The second, implies that right now, they are exempted from paying tax. It doesn't say anything about what happened in the past, or what was the situation before right now.