How a switch may be used intermittently? (2,3,3)
I believe the answer is:
on and off
'intermittently?' is the definition.
(I've seen this before)
'how a switch may be' is the wordplay.
I cannot really see how this works, but
'a' could be 'an' and 'an' is present in the answer.
This may be the basis of clue (or it may be nonsense).
'used' acts as a link.
Can you help me to learn more?
(Other definitions for on and off that I've seen before include "From time to time, not continually" , "spasmodic" , "From time to time, not continuously" , "Perhaps switch positions" , "Switch choices" .)