1·He has sustained his fierce social conscience from young adulthood through old age.
他从青年时代到晚年一直保持着强烈的社会良知。
—— 《柯林斯英汉双解大词典》
2·It peaks in young adulthood, levels out for a period of time, and then generally starts to slowly decline as we age.
它在青年时期达到顶峰，在一段时间内趋于平稳，然后普遍会开始随着年龄的增长而缓慢下降。
3·With this study, researchers examined early academic attention and socio-emotional skills and how each contributed to academic success into young adulthood.
通过这项研究，研究人员调查了早期的学术关注和社会情感技能，以及它们分别是如何影响青少年学术成就的。
4·Declining mental function is often seen as a problem of old age, but certain aspects of brain function actually begin their decline in young adulthood, a new study suggests.
心智功能衰退通常被视为老年问题，但一项新的研究表明，大脑功能的某些方面实际上在青年时代就开始衰退了。