By the time the decomposers are done, all of the original sun energy the plants captured has been used up.
(the decomposers; are done; T:the time) (the plants; captured; ) (all of the original sun energy the plants; has been used up; T:By the time)
the decomposers the plants all of the original sun energy the plants
are done captured has been used up
T:the time
T:By the time