The interesting point is that although energy can be converted from one form to another, it is impossible to convert all heat energy into work energy.
(energy; can be converted; from one form to another) (The interesting point; is; that although energy can be converted from one form to another, it is impossible to convert all heat energy into work energy)
energy The interesting point
can be converted is
from one form to another
that although energy can be converted from one form to another, it is impossible to convert all heat energy into work energy