题目： The phrase “heat recovery” refers to a ______.
A、 method of concealing the source of heat
B、 special form of air conditioning
C、 supplementary hot water system
D、 way of reclaiming and re-using heat
题目： The phrase “heat recovery” refers to a ______.
A、 method of concealing the source of heat
B、 special form of air conditioning
C、 supplementary hot water system
D、 way of reclaiming and re-using heat
