How switches switch from time to time (3,3,2)
I believe the answer is:
off and on
'from time to time' is the definition.
(I've seen this before)
'how switches switch' is the wordplay.
I cannot really see how this works, but
'switch' could be 'off' (I've seen this in another clue) and 'off' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for off and on that I've seen before include "the two sides at the Oval are this" , "switch positions" , "Intermittently" , "Now and then, here and there (3, 3, 2)" , "Now and then, stop and start" .)