cause VS purpose

[hela]

Dear teachers,

Would you please tell me what's the difference between an adverbial of purpose and an adverbial of cause?

Many thanks,
Hela

[Casiopea]

Would this list help?

http://college.hmco.com/english/raim...l/adverb_c.htm

[rhapsomatrics]

An adverb of cause,sometimes called reason,seeks to justify an action that has already been performed while an adverb of purpose gives justification to an inchoate or a futuristic action.In other words,an adverd of reason tells why an action was performed while that of purpose tells why an action will be performed or is about to be performed.Here are some examples:
A training programme is being arranged to enhance staff efficiency.The expression "to enhance staff efficiency"which can also be paraphrased thus"with a view to enhancing staff efficiency"is an adverbial(phrase:because of the non-finite verb"to enhance"),shows the purpose for the arrangement of the training programme...staff efficiency has not been enhanced yet(FOR ALL WE KNOW)
"The training programme was arranged because of staff inefficiency...the training was conducted and now we know why.
Note:An adverb of reason usually goes with 'because"..though there are a few exceptions.
Here are other examples:
"She ate the food /because she was hungry (cause/reason)
"She ate the food/so as to stay strong for the whole day(purpose)
Finally,an adverb of reason/cause answers the question "why" while that of purpose,as the appellation depicts,answers the question"for what purpose"