The hidden power of smiling

Ron Gutman: The hidden power of smiling


The vocabulary: 

* embark - go on board

* yearbook -a school publication with the most important events of a year and pictures of the graduating classes

* womb - a place where something is generated

* frown - to express a feeling by wrinkling the brow

* contagious - tending to spread from one to another

* smiler - someone who smiles :-)

* impair -  to reduce or weaken in strength, quality