Adverbs in He looked down and saw a highly unusual stone

The adverbs in the sentence are down and highly.

Explanation:

Down- this is modifying the word look.It shows where she looked.

Highly- this modifies the adjective unusual.The stone was not just unusual,the word highly there shows that it was to a higher level.

I hope this helps :)

its   c   : ) 0_  

i will try let me see what they are first