A.Their behaviors can be an invisible threat to society.
B.Their behaviors do not constitute a warning signal.
C.Their behaviors do not tend towards mental problems.
D.Their behaviors can be found in almost all teenagers on earth.
A.They are almost as liable to depression as the high-risk group.
B.They suffer from depression without showing any symptoms.
C.They do not often demonstrate risky behaviors as their peers.
D.They do not attract the media attention the high-risk group does.
A.It offers a new treatment for psychological problems among teenagers.
B.It provides new early-warning signals for identifying teens in trouble.
C.It may have found an ideal way to handle teenagers with behavioral problems.
D.It sheds new light on how unhealthy behaviors trigger mental health problems.