JAMB - English Language (1981 - No. 7)
The exercise must be done .... possible
as quick as
as quicker as
as quickly as
as most quick as
as most quickly as
Explication
The structure "as...as" is used for comparisons of equality, and the word that fits into this structure must follow correct grammatical form.
In this sentence:
The exercise must be done .... possible
We need an adverb to modify the verb "done", and the correct adverb form of "quick" is "quickly".