These days North Korea's ready for revolution (3)
I believe the answer is:
now
'these days' is the definition.
(I've seen this in another clue)
'north korea's ready for revolution' is the wordplay.
'north' becomes 'N' (abbreviation).
'korea's ready' becomes 'wo' (I can't justify this - if you can you should give a lot more credence to this answer).
'for revolution' says the letters should be written in reverse (letters revolve back).
'wo' in reverse letter order is 'ow'.
'n'+'ow'='NOW'
Can you help me to learn more?
(Other definitions for now that I've seen before include "straight away" , "Today" , "At this moment in time" , "Immediately" , "At present, this instant" .)