How does the polygraph work

A．Because future shock is caused by greatly accelerated rate of change.
B．Because future shock can not be predicated.
C．Because future shock prevent people from returning to a more familiar culture.
D．Because future shock can’t be explained in words.

A．To study how students remember English vocabulary by short-term memory.
B．To study how students learn English vocabulary.
C．To study how to develop student’s ability in English.
D．To study how long information in short-term memory is kept.