Parents complain that it is difficult to live with teenagers. Then again, teenagers say exactly the same thing about their parents. According to a recent survey, the most common arguments between parents and teenagers are those regarding untidiness and household chores. On the one hand, parents go mad over untidy rooms, clothes dropped on the floor and their children's refusal to help with the housework. On the other hand, teenagers lose their patience continually when parents tell them off for dropping the towel in the bathroom, not cleaning up their room or refusing to do the shopping at the supermarket.

The survey, conducted by St George University, shows that different parents have different approaches

to these problems. However, some approaches are much more successful than others. For example, those who yell at their teens for their untidiness, but later clear up after them, have fewer chances of changing their teens' behavior. On the contrary, those who let teenagers experience the bad results of their actions are more successful. For instance, when teenagers who don't help their parents with the shopping don't find their favorite food in the fridge, they are forced to reconsider their actions.

Psychologists say that the most important thing in relationships between parents and teenagers is communication. Parents should talk to their teens, but at the same time they should mull over what their children voice. Parents should scold their teens when they are untidy, but they should also understand that their room is their own private space. Communication is a two-way process. It is only by listening to and understanding each other that problems between parents and teens can be solved.

The phrase "mull over" in paragraph 3 is closest in meaning to __________