How long can human beings live？Most scientists who study old age think that the human body is（1）

C

C

to live no longer than 120 years.However，110 years is probably the longest that anyone could hope to live——if he or she is extremely healthy and lucky.Some scientists even say we can live as long as 130 years!Yet，our cells simply cannot continue to reproduce（2）

C

C

.They wear out，and as a result，we get old and eventually die.
   Even though we can't live forever，we can live a（3）

B

B

life than ever before.In 1900，Americans' average lifespan was only 47 years，but today it is 75 years!When does old age begin then？Sixty-five may be out-of-date as the（4）

C

C

line between middle age and old age.After all，many older people don't begin to experience physical and mental decline until after age 75.
   People are living longer because more people survive（5）

B

B

.Before modern medicine changed the laws of nature，many children died of common childhood（6）

A

A

.Now that the chances of dying young are much lower，the chances of living long are much higher due to better diets and health care.
   On the whole，our population is getting older.Then our population will have lasting（7）

C

C

on our social increases（社會），development and our way of life.Some people fear such changes will be for the worse，while some see（8）

B

B

，not disaster.Today，many men and women in their"golden year"are healthy，still active and young in（9）

A

A

if not in age.
   （10）

A

A

our society grows old，we need the contribution（貢獻）of our older citizens.With long lives ahead of them，they need to stay alive and be devoted.

（1）	A．chosen	B．improved	C．designed
（2）	A．rapidly	B．harmlessly	C．endlessly
（3）	A．busier	B．longer	C．happier
（4）	A．finishing	B．waiting	C．dividing
（5）	A．a(chǎn)dulthood	B．childhood	C．youthhood
（6）	A．diseases	B．fears	C．worries
（7）	A．problems	B．safety	C．influences
（8）	A．dreams	B．chances	C．choices
（9）	A．mind	B．voice	C．movement
（10）	A．As	B．When	C．How