A．By collecting information from the Internet.
B．By assessing ten different studies involving many participants.
C．By doing outdoor activities such as climbing and swimming.
D．By organizing many participants listening to different types of music.

A．Outdoor activities can cure many deadly diseases.
B．People with mental diseases benefit the most from outdoor exercise.
C．Healthy people needn't do much outdoor exercise.
D．A natural setting is very important to people's health.

A．Because she doesn't know how to prepare a speech.
B．Because she can't perform well as prepared.
C．Because she doesn't know where to put her draft.
D．Because she lacks experience in making speeches.