微笑是一件越来越难的事,就像都市里日渐稀薄的清新空气。微笑也因此变得弥足珍贵。when my mother was alive,she used to preach to me again and again about the value of just being nice Smiling is an increasingly difficult task, just like the lean and fresh air in the city. Smiles have become precious. When my mother was alive, she used to preach to me again and again about the value of just being nice