What does 'just now' mean? It indicates 'past' or 'present'?

[Duc]

Hello,

Please look at this excercise ,put the verbs in bracket into simple past or past continuous tense
Why you (interrupt) me just now? I (have) a very intersting conversation with Mr.pit

The answer is ''were...interrupting'', ''was having''.Although the topic of this excercise is''put the verbs in bracket into simple past or past continuous tense'' but I think we should use ''do..interrupt'' and ''was having'' because the phrase ''just now'' as far as I know is the same meaning as ''now'' or ''at the moment''.
Am I right ?
_________________
Don't see your shade think you are great

[Mister Micawber]

.
There are a couple of possible correct answers, but 'were...interrupting' is not one of them. The interruption could have happened immediately before or it could still be in process. These are OK:

A. Why did you interrupt...?... I was having
B. Why are you interrupting...?... I am having
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mister Micawber

[Yankee]

The phrase 'just now' can be used with either the present tense or the past tense. Depending on the context, it can mean either 'at present' or it can mean something similar to 'a minute ago'.

Why did you interrupt me just now?
(The interruption happened a very short time ago -- possibly just a few seconds ago.)

Sorry, but I don't have time to discuss that just now.
(I don't have time at the moment/at present.)
.