Complex sentence: Iran built it first metro network in Tehran in 1999, the second being in Mashad, finnished in 2011, and 5 more networks in other Persian cities are to be completed in the next years.
Split into simpler sentences: Iran built it first metro network in Tehran in 1999, the second being in Mashad, finnished in 2011. Five more networks in other Persian cities are to be completed in the next years.