Complex sentence: The tallest active skyscraper development currently taking place in Miami is One Bayfront Plaza, a mixed-use building proposed for 100 South Biscayne Boulevard, approved for construction since 2007, and scheduled to be completed in 2015.
Split into simpler sentences: The tallest active skyscraper development currently taking place in Miami is One Bayfront Plaza, a mixed-use building proposed for 100 South Biscayne Boulevard. The tower, a supertall skyscraper, has been approved for construction since 2007, when it was scheduled to be completed in 2015.