One must be patient with it for a long time (6,7)

'time' is the definition.
Both the definition and answer are singular nouns.
Maybe there's a link between them I don't understand?

'one must be patient with it for a long' is the wordplay.
I cannot really understand how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found in the answer.
'long' could be 'l' and 'l' is located in the answer.
This explanation may well be incorrect...

Can you help me to learn more?