Mandarin · Chapter 17 · Lesson 5 · Grammar primer
The two 了: completion vs change-of-state
Two unrelated particles written 了. The aspectual 了 sits right after the verb and marks an action as completed (我吃了饭); the change-of-state 了 sits at the very end and signals a new situation now holds (下雨了, 我会游泳了). The position test, what each one means, sentences where both appear, and the errors that catch every learner.
The lesson is a long-form read rather than a flashcard session. Open the primer below, work through it once, then come back and continue with the next lesson.
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