At the age of twelve years, the human body is at its most vigorous. It has yet to reach its full size
and strength, and its owner his or her full intelligence; but at this age the likelihood of death is least.
Earlier we were infants and young children, and consequently more vulnerable; later, we shall
undergo a progressive loss of our vigour and resistance which, though imperceptible at first, will
finally become so steep that we can live no longer, however well we look after ourselves, and
however well society, and our doctors, look after us. This decline in vigour with the passing of
time is called ageing. It is one of the most unpleasant discoveries which we all make that we must
decline in this way, that if we escape wars, accidents and diseases we shall eventually die of old
age, and that this happens at a rate which differs little from person to person, so that there are
heavy odds in favour of our dying between the ages of sixty-five and eighty. Some of us will die
sooner, a few will live longer-- on into a ninth or tenth decade. But the chances are against it, and
there is a virtual limit on how long we can hope to remain alive, however lucky and robust we are.
Normal people tend to forget this process unless and until they are reminded of it. We are so
familiar with the fact that man ages, that people have for years assumed that the process of losing
vigour with time, of becoming more likely to die the older we get, was something self-evident, like
the cooling of a hot kettle or the wearing-out of a pair of shoes. They have also assumed that all
animals, and probably other organisms such as trees, or even the universe itself, must in the nature
of things 'wear out'. Most animals we commonly observe do in fact age as we do if given the
chance to live long enough; and mechanical systems like a wound watch or the sun, do in fact run
out of energy in accordance with the second law of thermodynamics (whether the whole universe
does so is a moot point at present). But these are not analogous to what happens when man ages A
run-down watch is still a watch and can be rewound. An old watch, by contrast, becomes so worn
and unreliable that it eventually is not worth mending But a watch could never repair itself it does
not consist of living parts, only of metal, which wears away by friction. We could,at one time,
repair ourselves well enough, at least, to overcome all but the most instantly fatal illnesses an
accidents. Between twelve and eighty years we gradually lose this power; an illness which at
twelve would knock us over, at eighty can knock us out, and into
our grave. If we could stay as vigorous as we are at twelve, it would take about 700 years for half
of us to die, and another 700 for the survivors to be reduce by half again.

New words and expressions 生词短语

infant 婴儿(会说点话)
baby 婴儿(不会说话)
the infant industry 新兴产业
in its infancy 在初始阶段
vulnerable 脆弱的
be vulnerable to 受不了
fragile 脆弱
barefaced 厚颜无耻的
defenceless 脆弱的(不设防的,无保护的)
imperceptible 感觉不到的
(大多数 p 开头的形容词，反义词加 im)
invisible 看不到的
indiscernible 观察不到的
minute 微小的
subtle 细微的
steep 急转直下的（陡峭的）
steep demand 苛刻的要求
ageing 老化
aged wine 陈酿
odds 可能性
likelihood 可能性
It’s odds that…
The odds are…
There are odds… 都是 ……有可能
Odd 怪异的
virtual 实际的
robust 强健的（乐百氏）
muscular 强壮的
athletic 壮的
kettle 水壶
wearing-ou t 穿破
thermodynamics 热力学
moot point 有争议的
run-down 破旧的
decrepit 衰老
dilapidated 破旧的
shabby 破旧的（房子）
Notes on the text 课文注释
1.vigorous 后省略 stage同义词:livelyrobust dynamic
2.yet=however yet 可在句中,不用标点however 用在句中要用逗号
3.stealthy slide out of room 溜出房间 play truant 逃学
4.injection
cry one’s eyes out 嚎啕大哭
5.undergo 经历 up and down/ lows and highs 沉浮
6.the passing of time 时光流逝
7.heavy odds 极大可能
8.virtual:physical
9.寿命 life-span life expectancy longevity
10.tend to 倾向，不由自主
11.spoil oneself 糟蹋自己
12.the …the …并列比较
13.organism 有机体
14.wind 上发条wound 上了发条的run-down 发条不紧的
15.but=except
16.fatul=deadly 致命的