comma usage       In the sentence below, am I right about the usage of the comma after a subordinate clause?   
When I asked her, "Would you like a cup of tea?", she said, "No, thank you."   
I am not confident about ...?",  
Would anybody tell me if the comma is necessary or not? 
Or, is there any other better way to write?   
Thank you.    
Chikako      |