A．Carry little luggage．
B．Go through a health check．
C．Arrive 10 minutes earlier for boarding．
D．Undergo security check．
A．To improve his skating techniques．
B．To climb mountains．
C．To take a vacation．
D．To learn to ski．
A．Because her sister lives there．
B．Because she attends college there．
C．Because she lives thirty miles from there．
D．Because she had the vacation there last year．
A．The cold weather．
B．The low humidity．
C．The high altitude．
D．The changing climate．