I cannot understand very well
I have a puzzle about a short text:

A mother and son washing dishes while father and daughter were watching TV, suddenly, a dish droped down, and there was complete silence.
The girl looked at her father and said,"It was Mom."
"How do you know?" asked her father.
"She didn't say anything."

So How to explain the sentence"asked her father". From the whole text, it means father ask her daughter, but i am not sure how the "asked" used,it just represent the past tense? or other meanning?

Question

I cannot understand very well
I have a puzzle about a short text:

A mother and son washing dishes while father and daughter were watching TV, suddenly, a dish droped down, and there was complete silence.
The girl looked at her father and said,"It was Mom."
"How do you know?" asked her father.
"She didn't say anything."

So How to explain the sentence"asked her father". From the whole text, it means father ask her daughter, but i am not sure how the "asked" used,it just represent the past tense? or other meanning?

Answer

It just shows that the father asked the daughter. It clarifies who was speaking.

Answer

Susan is right, but just to clarify even further, authors will chose a tense to describe the actions of characters outside of dialogue.  In this case the author chose to use the past tense so that is why it is used that way.  If they had written it in a different way it could say: 
"The girl looks at her father and says, 'It was mom'.
'How do you know?' asks her father.
'She didn't say anything'."
It all depends on the author's point of view.  Hope that helps!!