sentences: if something comes from something else then that something else is a source of that something & oil is a source of gasoline ->  gasoline comes from oil  gasoline comes from oil & oil is a nonrenewable resource ->  gasoline comes from a nonrenewable resource  gasoline comes from a nonrenewable resource & a nonrenewable resource is limited in supply ->  gasoline comes from a resource that is limited in supply  for something to be replaced means for something else to be used instead of that something & if a resource is limited in supply then that resource needs to be replaced ->  if a resource is limited in supply then something else needs to be used instead of that resource  gasoline comes from a resource that is limited in supply & if a resource is limited in supply then something else needs to be used instead of that resource & an automobile is a kind of vehicle0 ->  something else must be used instead of gasoline because gasoline comes from a limited resource  an automobile is a kind of vehicle & vehicles usually require gasoline to operate ->  automobiles usually require gasoline to operate  automobiles usually require gasoline to operate & alternative fuels are being used in some automobiles ->  alternative fuels are being used in some automobiles instead of gasoline  something else must be used instead of gasoline because gasoline comes from a limited resource & alternative fuels are being used in some automobiles instead of gasoline -> alternative fuels are being used instead of gasoline in automobiles because gasoline comes from a limited resource