To avoid most problems, you really need to communicate! Honestly though, I really just stopped listening years ago. When she carries on a conversation, I just grunt once in awhile.
Occasionally, you will notice that her conversation has stopped. She may have asked you a question. At this time you will NEED to make eye contact. IF she is making eye contact with you, she is probably waiting on a response… What you are looking for now is the position of her eyebrows. If they are raised, give her a generic positive answer. If her eyebrows are lowered, respond with something negative, mild and generic. Do not attempt to guess as to anything you think she might have said. You will get burned.
Some times, you just can’t read her eyebrows, they may be freshly plucked, she could be ready to sneeze.. Who knows that reason?… At this point you need to seek clarification without admitting that you were not paying any attention! I usually state something to the effect of, “I want to make sure I have this right. Run that last part by me again.” Now, please understand that you are NEVER going to get a repeat of JUST the last part. But with any luck you have dodged the “You’re not even paying attention!” bullet. And she can go back to her conversation while the theme from dueling banjos plays softly in your head.