These are called "fossil fuels" because originally they were living things, that have transformed over millions of years into "hydro-carbons".
(These; are called; fossil fuels" because originally they were living things) (they; were; T:originally) (living things; have transformed; T:over millions of years; into "hydro-carbons)
These they living things
are called were have transformed
fossil fuels" because originally they were living things
T:originally
T:over millions of years into "hydro-carbons