To be about to refers to actions that are going to happen very soon.
The structure of to be about to in the sentence is:
Subject + be about to + infinitive of the verb + …
NOTE: Sometimes we put just after the verb to be.
- I‘m about to have a surgery for my blindness.
- He is about to feel dizzy because of alcohol.
- They are just about to show students a skeleton.
We use to be about to for near future actions that are going to happen very soon.
We cannot use to be about to with time expressions, so in that case, we use just Simple Present.
Sometimes we use just to give more emphasis.