Theory:

     ‘What are you looking at?’
 
     It was a disembodied voice at first. Moments later a girl stood framed between dark red hollyhocks staring at the man. She was only twelve or thirteen, with lively eyes and long black hair.

     ‘I’m looking at the house. Is it yours?,’ he asked.

     'No. It's my father's. Why? Do you want to buy it?'

     'And what does your father do?'

     'He's only a colonel.'

     'Only a colonel?'

     'Well, he should have been a brigadier by now.'
 
     The man burst out laughing.
Explanation:
 
Suddenly a voice came up, asking him what he was seeing.
 
It was a distinctive voice. A girl looked at the man from the hollyhocks. She was just twelve or thirteen, with long black hair and eyes full of energy.
 
The man asked if the house was that girl's, and that he was looking at it.
 
She replied that it was her father's and if the man wanted to buy it.
 
The man asked what her father does?
 
She replied that he is only a colonel.
 
The man was surprised to hear the words "only a colonel?" why this word" only"?
 
The girl replied that he should have been a brigadier by then.
 
The man laughed out without control.
 
Meanings of difficult words:
 
Number
Word
Meanings
1.
 Disembodied  Separated.
2.
 Lively  Energetic.
Reference:
State Council of Educational Research and Training (2018). Term-1 English Standard-9. I Can’t Climb Trees Anymore - Ruskin Bond (Slightly adapted) (pp. 157-160). Published by the Tamil Nadu Textbook and Educational Services Corporation.