Doctor：      小题1:       

Michael：Doctor, I am often tired.

Doctor：Let me see. Oh, nothing serious. But you are getting too fat.

Michael：      小题2:      

Doctor：Don’t worry. How often do you exercise?

Michael：Exercise? Hardly ever.      小题3:     

Doctor：And how often do you eat junk food?

Michael：       小题4:      It’s my favorite food.

Doctor：I see. You should do sports and eat less junk food.

Michael：      小题5:        Thank you.

简述影响肥肝生产的因素。