English - Grammer

sure, you can.

i am just going to the market. it means 'for a short time'.

i am just going to have a look. it means 'you will look and wont buy it'.

in chinese, it's like 只是。

is/am/are going to = future tense which has the meaning that there is something certainly will happen soon

I am going to go to school. (future tense)
I will go to school. (future tense)
I am going to school. (present continuous tense)

Yes, you can say so.

That means you want to do this at that point of time.