Complex sentence: The World Indoor Championships was the first of two significant athletics events to take place in Doha in 2010--the inaugural 2010 IAAF Diamond League will begin with the Qatar Athletic Super Grand Prix meeting in May.
Split into simpler sentences: The World Indoor Championships is the first of two significant athletics events to take place in Doha in 2010. The inaugural 2010 IAAF Diamond League will begin with the Qatar Athletic Super Grand Prix meeting in May.