How old is "old"？ The answer has changed over the years. Two hundred years ago, you were o

ld at 35. That was the average life expectancy then. At the turn of the 19th century, as medical knowledge advanced, the average life expectancy increased to 45. In 1950, 70-year olds were really old. Today, a healthy 70-year-old is looking forward to many more active years.

So, how old is old？ The answer is one you' ve heard many times, from all sorts of people. "You are as old (or young) as you feel." The calendar simply tells you how many years you have lived. Your body tells you how well you' ve lived.

"Youth", wrote an unknown author, "is not a time of life--it is a state of mind. Nobody grows old by living a number of years; people grow old by deserting (抛弃) their ideals."

Old is a point of view. Alice Brophy, when she was with the New York City Commission for the Aging, said, "It annoys me when people say, 'Gee, you look young for your age. ' What does that mean？ Is there some model that you' re supposed to look a certain way at 65 and 75 and 85？ You know, you can die old at 30 and live young at 80."

It is often believed that most older people are in poor health. But the fact is that there are neither biological nor physiological (生理学的) reasons to connect poor health with growing older. Older people are more likely to be affected with illness and physical disabilities than you are, but old age itself is not a disease. It's possible to remain physically fit throughout your life.

Which of the following statements is NOT true according to the passage？

A．The concept of "old" is differently defined in different times.

B．Nobody can remain physically healthy throughout the life.

C．The progress in medical knowledge has contributed a lot lo longer lives of us.

D．Older people may get ill and physically disabled more easily than younger ones.