An example of therefore is saying that you got a cold and then had to stay home from work.
The storm made the forest pitch dark; therefore, searching was useless until it abated.
"My men have been scattered," said the king, "and therefore, no one is with me."
You had no real knowledge and therefore no way to make a wise decision.
He therefore gave him many beautiful gifts and everything that could please a prince.
If you are able to consume more energy, you can do more work and therefore create more.