chronic

Compared meaning: lasting for a very long time (adjective).

比较义项：持续时间很长，历时长久（形容词）。

• long

  The most common, neutral word for lasting a great amount of time; used broadly for time periods, waits, meetings, books, with no special connotation.

  最普通、中性的词，表示持续时间很长；广泛用于时间段、等待、会议、书籍等，没有特殊的感情色彩。

  It was a long meeting, and everyone was tired by the end.

  这是一场很长的会议，到最后大家都累了。

• extended

  Describes something made longer than originally planned or expected, often formally, such as a stay, deadline or warranty; implies a deliberate extension.

  指某事被延长到超出原计划或预期的时间，常用于正式场合，如停留、截止日期或保修期；暗示是刻意延长的。

  The airline offered passengers an extended stay at the hotel due to the delay.

  由于航班延误，航空公司为乘客提供了延长的酒店住宿。

• lifelong

  Specifically means lasting for a person's entire life; used for relationships, habits, dreams or conditions that never end.

  特指持续一个人的一生；用于形容关系、习惯、梦想或永远不会结束的状况。

  Her lifelong dream was finally realized when she opened her own bakery.

  当她开了自己的面包店时，她终身的梦想终于实现了。

• chronic 本词

  Describes a problem, illness or bad habit that persists over a long time or keeps recurring; carries a negative connotation.

  形容一个问题、疾病或坏习惯持续很久或反复发生；带有负面的感情色彩。

  Chronic stress at work eventually affected his health.

  长期反复的工作压力最终影响了他的健康。

Long, extended, lifelong, and chronic all describe something lasting a long time. Long is the most common, neutral word. Extended means made longer than planned, for a stay or deadline. Lifelong means lasting a person's whole life. Chronic describes a problem that keeps happening.

这几个词都能表示“持续时间很长”，但语气、正式程度和搭配不同：long最中性常用，extended强调被刻意延长，lifelong特指贯穿一生，chronic多用于负面、反复出现的问题或疾病。这里不比较 long 表示“长的”（指距离长）的意义，也不比较 extended 用于 extended family（大家庭）等其他用法。