If heat and work are the only forms of energy transferred between the systems and surroundings of a closed system, E2 - E1 = q + w.
(heat and work; are; the only forms of energy transferred between the systems and surroundings of a closed system,) (the only forms of energy; transferred; between the systems and surroundings of a closed system)
heat and work the only forms of energy
are transferred
the only forms of energy transferred between the systems and surroundings of a closed system,
between the systems and surroundings of a closed system