Complex sentence: Following principles that came to be known as transit-oriented development, the City of Cambridge zoned the area immediately near the station for high rise buildings and over the next 20 years a mini-city has developed with office and R&D buildings along with high rise housing.
Split into simpler sentences: Following principles that came to be known as transit-oriented development, the City of Cambridge zoned the area immediately near the station for high rise buildings. Over the next 20 years, a mini-city developed with office and research and development buildings, along with high rise housing.