单项选择题
A．are trying activities such as bungee jumping B．are climbing the highest mountains C．are close to death in sports D．are looking for adventures such as exploring unknown places
A．positive B．negative C．objective D．subjective
A．Dangerous Sports; What and Why B．The Boredom of Modem Life C．Bungee Jumping: Is It Really Dangerous D．The Need for Excitement