了 in Complex Clauses
Review how 了 behaves when advanced sentences have more than one clause.
Pattern
clause + 了, second clause / sentence-final 了
Track whether 了 marks completion, change, or the whole situation.
他完成了任务以后，就回家了。
When to use 了 in Complex Clauses
In complex sentences, 了 can attach to a completed verb, mark a changed situation at the end, or appear in both roles.
天气冷了，我们别出去了。
The weather has turned cold; let us not go out.
我看了邮件，才知道计划变了。
Only after reading the email did I learn the plan had changed.
问题解决了，大家就放心了。
Once the problem was solved, everyone felt relieved.
她来了以后，会议才开始。
Only after she arrived did the meeting begin.
Common traps
- Do not treat every 了 as past tense.
- A sentence can contain both verb 了 and sentence-final 了 for different reasons.
- After 以后, the first 了 often marks completion before the next event.
Vocabulaire de soutien
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