While elated to have snatched victory in the Manchester derby, Sir Alex Ferguson was left with mixed emotions after missing out on the chance to rout the Reds' near neighbours.
The young man still wanted to ask something, but the wise man stopped him and said, "When we are talking about the importance of today, we have wasted a lot of it."
Vanke is using more solar and other renewable energy, and adopting prefabrication techniques, borrowed partly from Japan, that are less wasteful than standard Chinese construction.
The information it provides allows a coach closely to monitor the stamina of an athlete, determine his level of fatigue more accurately and help work out where he might be wasting energy.
Similarly, a plant or animal cannot squander all its energy on growing a big body if none would be left over for reproduction, for this is the surest way to extinction.