Complex sentence: Länsimetro (the Western Metro Extension, Swedish: Västmetron) is an extension of the Helsinki Metro system under construction from central Helsinki, Finland, to the neighbouring city of Espoo.
Split into simpler sentences: Länsimetro (the Western Metro Extension, Swedish: Västmetron) is an extension of the Helsinki Metro system. The line will run from central Helsinki, Finland, to the neighbouring city of Espoo.