A recent National Public Radio program examined the disappearance of some of the first words we were probably taught - "please" and "thank you." Other polite phrases are also disappearing. "You're welcome" has been replaced by "sure," "no problem," "you bet" or "enjoy."   Are we becoming ruder, or are patterns of speech merely updating for changing times?   Peter Post, director of the program, argues about people stopping using "you're welcome". He says, "Thank you" is an expression of appreciation one person offers another. To respond "No problem" is to ignore this acceptance as really being undeserved. By responding with a simple "you're welcome," Post adds, a person admits the thanks and shows appreciation for the person giving it.   Whatever polite vocabulary you believe is fading, sociologist Gregory E. Smith says that such fading is a sign that we're becoming ruder as a society. "Saying please and thank you, asking permission, offering help, and following up on solutions to problems are no longer as important," he says. In 2011, 76 percent of people surveyed said Americans are becoming less civil.   But could it be that it's simply the words we're using that are changing? Actually, the principles of respect, consideration and honesty are universal and timeless, but manners do change. For example, it's important to greet people when you see them, though the form of greeting has changed over time. "How do you do," for instance, became "Hello, how are you?" which changed into "Hello, how are things," or "How's it going?". As for "no problem", if the appreciation is expressed in a sincere manner, many Americans think they do not see its use as a loss of politeness. According to the text, when you meet a person for the first time,   _  .
you should say "How do you do?" first you still need to express your greetings you'd better change your manners you must care about your expression