Everything takes time which you may say you haven't got (3,3)
I believe the answer is:
all day
'you may say you haven't got' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'everything takes time' is the wordplay.
'everything' becomes 'all' (I've seen this before).
'takes' means one lot of letters go next to another.
'time' becomes 'day' (day is a kind of time).
'all'+'day'='ALL-DAY'
'which' acts as a link.
Can you help me to learn more?
(Other definitions for all day that I've seen before include "morning and afternoon" , "From dawn to dusk" , "until even" .)