Complex sentence: Montenegro entered Intensified Dialogue with NATO in April 2008, adopted an Individual Partnership Action Plan in June 2008, and began full membership with the Adriatic Charter of NATO aspirants in May 2009.
Split into simpler sentences: Montenegro entered Intensified Dialogue with NATO in April 2008, and adopted an Individual Partnership Action Plan in June 2008. Montenegro also began full membership with the Adriatic Charter of NATO aspirants in May 2009.