Occasionally the present linked with the past (3,3,4)
I believe the answer is:
now and then
'occasionally' is the definition.
(I've seen this in another clue)
'present linked with the past' is the wordplay.
I cannot quite see how this works, but
'present' could be 'now' (both can mean the current period) and 'now' is located in the answer.
'with' could be 'and' and 'and' is located in the answer.
'past' could be 'then' (similar in meaning) and 'then' is found within the answer.
No letters remain.
This explanation may well be incorrect...
'the' acts as a link.
Can you help me to learn more?
(Other definitions for now and then that I've seen before include "At times" , "Sometimes" , "Occasionally" , "making a historical contrast" .)