--description--

In the beginning of the dialogue, Maria says Are you into photography? to ask if Bob likes photography. Now that she knows he does, she asks How long have you been into photography? to know the amount of time that has passed since he started enjoying it.

Since the question is about duration from the past up until the present, you use the Present Perfect tense.

Remember that the form of the verb to be for the present perfect is been. For example, I have been in a traffic jam for an hour.

How long...? is used to ask questions related to duration. For example:

How long have they been testing the new app? - This question is about the duration of testing.

--fillInTheBlank--

--sentence--

BLANK have you BLANK into photography?

--blanks--

How long

--feedback--

These two words are used to ask about duration of time. The first letter of the first word is capitalized.

been

--feedback--

It's the verb to be in the present perfect tense.

--scene--

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