> i want to get all the possible question from that paragraph

Do you mean that you want to extract all the sentences that end in a question mark?

Untested (so don't laugh, all you Ruby grownups):

def questions(para)
    ans = []
    para.split(/[\.\?\!] /).each do |sn|
        ans << sn if sn ~= /\? $/
    end

    return ans
end

(That won't cope with brackets.)  Said the Vicar: "Or quotes."   But it's a starting point -- assuming that that was what you meant.

Presumably someone smarter than me could do better with a single regex.

-- 
This is a test of the Emergency Broadcast System.  If this had been an
actual emergency, do you really think we'd stick around to tell you?