VNEN
qua lại 
to come and go [ qua ] : after, by, through, over; last (week, day, etc.); to pass by, go across, cross over
[ lại ] : (1) again; against, over again, back towards; resume, re-; (2) to come, reach, get to; (3) (indicates something is contrary to expectations)
交往 
quan hệ qua lại; giao du; qua lại, mối quan hệ