Sentence:  One day , Ching had told him ( <WSD>smiling</WSD> , patting him on the back ) as they walked to the weekly conference of squad leaders , `` Keep it up , your squad is good , one of the best , keep it up , keep up the good work '' . 
Meaning of the word marked with <WSD> tags:  change one's facial expression by spreading the lips, often to signal pleasure