as much as, to the extent of, enough to
Verb +
This formation uses the same verb before and after
Potential Verb +
Uses the potential form of a verb before
走れる
Run as much as one can
Dictionary Form Verb +
Uses the dictionary form of a volitional verb before
買う
Buy as much as one wants
Non-volitional Intransitive Verb +
Uses a non-volitional intransitive verb to describe a state or action naturally reaching its absolute limit without human intention.
伸びる
Stretch as much as it can
The verb before
できる
The fixed expression できる
できる
Modifies a noun to have as much of a certain quality as possible. The adjective connects to the noun using its standard modifying form.
できる
A car as new as possible
できる
A road as safe as possible
できる
Modifies a verb to describe performing an action to the greatest degree possible.
できる
Wake up as early as possible
This is a set phrase using the potential form of the verb する. Unlike the verb pattern, you do not repeat the adjective or adverb.