A．Facial expressions can only reflect emotional states．
B．Facial expressions may help people survive．
C．Baring the teeth means the same to people all over the world．
D．Humanemotions that were not expressed would become less intensive．
A．knewlittle about Western culture
B．showed distinctive facial expressions
C．werefamous for their solitude
D．hadnever been taken photographs of before
A．thereis no link between emotions and facial expressions
B．people's facial expressions can only reflect their emotional states
C．people's emotional states cannot be influenced by their facial expressions
D．thecausal link between emotions and facial expressions is bidirectional
A．people might have different expressions for the same emotion
B．pleasant feelings often stimulate Duchanne smile
C．"crow's feet" wrinkles often accompanied the Duchenne smile
D．keeping a stiff upper lip was useful for handling stress