1. 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,
    我们对人总是要衰老的现象并不陌生，多年来就已认识到。生命随着时间流失而丧失活力，人随着年龄的增长而接近死亡，这是不言而喻的，

2. This decline in vigour with the passing of time is called ageing.
    这种随着时间流逝的活力衰退就叫做衰老。

3. This decline in vigour with the passing of time is called ageing.
    这种随着时间流逝的活力衰退就叫做衰老。

4. Later, we shall undergo a progressive loss of our vigour and resistance which,
    再迟一些，我们就要经历生命力和抵抗力逐步衰退的过程。

5. This decline in vigour with the passing of time is called ageing.
    生命力随着时间的流失而衰退叫做衰老。

6. At 40, he was in his prime and full of vigour.
    他40岁时正年富力强.