The advantage of these contracts is that if property is destroyed by a peril not specifically excluded the insurance is good.

A．the failure to keep to a routine of methodical and intensive work
B．changing from one subject to another
C．unwillingness to follow a systematic plan
D．applying oneself to a subject only when one feels inclined

A．has made all people see the danger of drugs
B．has succeeded in dissuading people from using drugs
C．has been effective only to a certain degree
D．has proved to be a total failure