仔细阅读1 

46 What do velieve about aging?  

B) They just cannot do anything about it.

47 How do many scientists view aging now? 

A) It might be prevented and treated. 

48 What does Alex Zhavoronkov think of "describinq aging as a disease"?

 D) It will motivate doctors and pharmacists to find ways to treat aging.

49 What do we learn about the medical community? 

C)They can contribute to people's health only to a limited extend.

50 What does Professor Leonard Hayflick believe? 

 A) The human lifespan cannot be prolonged.