What’s the doctors’ opinion about hobbies Hobbies help to make our lives ______ .

A．how students remember English vocabulary by short-term memory
B．how students learn English vocabulary
C．how to develop students’ ability in English
D．how long information in short-term memory is kept

A．smoking in forests
B．changing the attitudes and behavior of millions of people
C．the chief causes of forest fires and their prevention
D．advances in knowledge of fire weather