When an adverb modifies anything besides a verb (like an adjective, another adverb, or noun phrases for example) it is placed in front of what it modifies . 
Je suis vraiment diabolique.
I am truly evil. 

Il a vécu dans la jungle bresilienne très longtemps.
He lived in the Brazilian jungle for a very long time. 

Manner Adverbs
In simple sentences the adverb follows the verb. 
Je parle étrangement
I speak strangely. 
A big No-No is  placing the adverb before the verb - as is possible in English. Doing this in French is outrageous and horribly wrong. (Okay, I might be exaggerating somewhat)

But, in sentences that use the passé composé, usually adverbs immediately follow the auxiliary verb (avoir or être). 

J'ai complètement oublié de faire le travail.
I completely forgot to do my homework. 

Donations | Contact Us | Blog