1、老龄化已成为一个社会问题。

Aging has become a social problem.

2、人们反对这一看法来自于出生率的下降。

People are against that this view causes from the decrease of birth rate.

3、人们寿命的长短取决于种种因素。

A man's life span depends on various facts.

4、估计寿命是预计一个人能活的平均年数。

The estimated life span is to predict the average.

5、长寿在改变我们的生活，改变我们的社会。

Longevity is changing our life and our society.