They had longer life expectancies than their parents.是什么意思？

They had longer life expectancies than their parents.

他们比上一辈人的预期寿命要长。

they

pron. 他/她/它们，人们，大家，政府，当局，她们；

例句
The storms had abated by the time they rounded Cape Horn.
他们绕过合恩角时，暴风雨已经减弱。

had

v. 有（ have的过去式和过去分词 ），（亲属关系中）接受，拿，买到；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

longer

adj. 比较久的，（距离，长度）长的( long的比较级 )，长时间的，（因忙或不愉快等）似乎比实际时间长的，长音的；

例句
After about three months, I was no longer addicted to nicotine.
大约3个月后，我就不再对尼古丁上瘾了。

life

n. 生活，生计，生命，性命，一生，寿命，人生，尘世；

例句
In his later life he became even more absent-minded.
他晚年变得愈加健忘了。

expectancies

n. 期待，期望( expectancy的名词复数 )；

例句
They had longer life expectancies than their parents.
他们比上一辈人的预期寿命要长。

than

conj. 比（用于比较级），宁愿…而不愿，除…以外，一…就；prep. 超过，比；

例句
...more than a thousand acres of land.
1,000多英亩地

their

pron. 他（她，它）们的，在提及性别不详的人时，用以代替 him 或 her；

例句
Their permissiveness toward their children reflects the wild abandon of their own lives.
他们对孩子的放任折射出他们自身生活的放浪形骸。

parents

n. 双亲（ parent的名词复数 ）；

例句
Some parents believe a boy must learn to stand up and fight like a man.
有些父母认为男孩子必须学会像男子汉一样顶天立地，勇于抗争。