"Can do" Form grammar?


> Watashi wa hon o yomeru hayai dekiru. = I can read books quickly.

I know that you can either conjugate the verb to be -eru or -rareru, or you
could leave the verb in the plain form and add "koto ga dekiru". So, for when
you conjugate the verb, do I still add dekiru, or do I take it out? Then will
the sentence make sense?

ありがとう！




The possible translations would be:

>   * 私は本を速く読める。  
>  Watashi wa hon o hayaku yomeru.
>   * 私は本を速く読むことができる。  
>  Watashi wa hon o hayaku yomu koto ga dekiru.
>

You only need one potential expression, just as you only need only one "can"
in English.

"Hayai dekiru" is ungrammatical and makes no sense. Do you know how to turn an
adjective into an adverb (or how to use Japanese adverbs in general?) If not,
please read [this](http://www.guidetojapanese.org/learn/complete/adverbs). You
certainly need "quickly" rather than "quick" in this English sentence, don't
you? Likewise, you will need 速く (≒quickly), not 速い (≒quick), in your Japanese
translation.

