The words or group of words, which indicate the reason or cause behind an action, being or quality, are called the Adverbs of Reason.
- The man was bleeding profusely. Therefore, he was hospitalised.
- Rashmi worked hard. So, she won the first prize.
- There was a jam on the roads. Hence, we took a detour.
- You were at fault. That is why, you were punished.
In the above examples, therefore, so, hence and that is why tend to indicate the
reason behind the actions (verbs) was hospitalised, won, took a detour and were punished.
Hence, they are all adverbs of reason.
Adverbs of reason indicate the answers to the questions ‘why‘, ‘due to what reason‘, ‘because of what reason‘. Mostly, an adverb of reason appears at the start of a sentence.