Question frame (How long have you been living in chicago?)

[Pavanhotscan]

my friend is staying in chicago , i know that .

then i asked him " how long have you been living in chicago ?"

or

" how long have you been in chicago "

which one is correct ?

can you give me an explanation for the above question ?

[Mister Micawber]

.
Both are fine.
.
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Native English teacher at Mister Micawber's