A．aerobic exercise help prevent lung diseases
B．vigorous exercise is dangerous for poeple over 50
C．weight lifting can do much good to the frail elderly
D．the more exercise one does, the less one is likely to die

A．traditional terrorism was mainly driven by religious fervor
B．ideological differences will continue to be a cause of terrorism
C．attacks from small terrorist groups will increasing
D．the high-tech weapons will greatly facilitate terrorist attacks