练习材料：
[Day 1796 2019-08-27]
Lesson 37-1 The process of ageing 衰老过程
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.
任务配置：L0+L1+L4
知识笔记：
vigorous adj. 充满活力的; 果断的; 精力充沛的; 强壮的; 强健的;
undergo v. 经历，经受(变化、不快的事等);
vigour n. 精力; 力量; 活力; 热情;
resistance n. 反对; 抵制; 抗拒; 抵抗; 反抗; 抗力; 抵抗力;
imperceptible adj. (小得) 无法察觉的，感觉不到的;
练习感悟：
