Which one is correct?

"It should use." is not viable as a sentence by itself. However, this sequence of words can validly appear as part of a longer sentence.

"It should be used." is possible as a sentence.

More context is needed to determine what is the best way of saying what you mean.

Thanks, GPY.
Yes, 2nd one is possible. But why? Is 'use' transitive or intransitive verb?
I appreciate your valuable time.

mizansinha007Yes, 2nd one is possible. But why? Is 'use' transitive or intransitive verb?

In Modern English, the verb "use" is always transitive (if we exclude the past tense structure "X used to + infinitive").

Your first example is not a valid sentence because the object is missing.

For interest, there is at least one intransitive sense of "use", meaning to use drugs. So, "He's using" could be a valid sentence. However, 99.9% of the time "use" is transitive.

GPYFor interest, there is at least one intransitive sense of "use", meaning to use drugs. So, "He's using" could be a valid sentence. However, 99.9% of the time "use" is transitive.

But isn't the object (drugs) implied? I guess technically "use" is still transitive even in this case, but then again, it's hard to be all technical when it comes to informal speec

I would say it is intransitive nonetheless. I don't think you count object-less verbs as transitive just because an implied object could be added. That's not a particularly uncommon case.

... I've just been checking various dictionaries, and not many seem to separately list this use. However, Merriam-Webster does actually list it as intransitive:

http://www.merriam-webster.com/dictionary/use

The Shorter Oxford lists three intransitive uses of which one is the aforementioned "used to" and another the "drugs" one. There is a third I've never heard and I think we can safely ignore here that is labeled "Scot.": "Accustom oneself or become accustomed to something".

GPY... I've just been checking various dictionaries, and not many seem to separately list this use. However, Merriam-Webster does actually list it as intransitive: http://www.merriam-webster.com/dictionary/use

Then I stand corrected as to the wording of my first post in

ozzourtiThen I stand corrected as to the wording of my first post in this thread. They say "never say never", but from now on I say "never say always".

I think what you said was correct for all practical purposes for the OP. I only mentioned it as a curiosity really.