right now, a billion people are chronically hungry.
2017年6月六级真题（第二套）听力 Section C
When Liu, the UCLA sleep researcher and professor of medicine, brought chronically sleep-restricted people into the lab for a weekend of sleep during which they logged about 10 hours per night, they showed improvements in the ability of insulin to process
2015年12月六级真题（第二套）阅读 Section A
柯林斯高阶英汉双解学习词典释义
ADJ
(疾病、残疾)慢性的，长期的
A chronic illness or disability lasts for a very long time.
You can describe someone's bad habits or behaviour as chronic when they have behaved like that for a long time and do not seem to be able to stop themselves.