Although senior citizens can make contribution, the demographic trend may lead to some problems.

尽管老年人能够做出贡献，但人口结构变化趋势可能会引发一些问题。 

One problem about an aging population is that the expense will escalate in health care, imposing a burden on taxpayers.

人口老龄化带来的一个问题是医疗保健方面的费用将会不断攀升，这给纳税人造成了负担。